Earlier this week I was working from home in the morning. I had the radio on in the background. My normal choice of oral wallpaper is BBC Radio 4. It’s often on, but I’m rarely ‘listening’ to it. I rely on the ‘cocktail party effect’ to pick up on anything vaguely relevant. In other words, listening to the radio for me is a bit like being at a gathering where there is a buzz of conversation in the background. In the main, what we ‘hear’ is filtered out, but if someone where to say something particularly relevant to us, such as our name, then it would tend to attract our attention. So, I am generally deaf to items on such matters as the spotting of a rare bird on a remote Scottish island and the minutiae of fiscal policy here in the UK, but when something about health or science pops up, I can suddenly be all ears.
So, earlier this week my attention was grabbed by an item on the debate about whether the time limit for termination of pregnancy should be dropped from 24 weeks (where it stands now) to 22 or 20 weeks. By the way, this blog article is not ethically, morally or religiously driven, it about science, or rather, the limitations of it.
One side of the argument here states that the abortion time limit should be brought down because babies can (and do) survive when born at an age lower than the current 24-week cut-off. Those opposing the change have generally used the argument that the ‘evidence’ shows that the survivability of infants born very prematurely has not changed in recent years. So, if 24 weeks was good enough when the limit was set, it is good enough now.
The obvious riposte to Gordon Brown’s (and others’) ‘scientifically-based’ argument is that there’s no reason to assume that just because the survivability of very premature infants has not changed, that the abortion time limit right. Maybe we got it ‘wrong’ the first time round and there’s an argument for reviewing the limit.
One individual supporting a review was a woman who was interviewed on Radio 4 who, if I remember correctly, delivered a child at 22 weeks gestation. The child was, she said, left to die. However, because after 36 hours this child had not died, it was duly treated with medical care and survived. According to the mother, while the child was (naturally) a slow-starter, he had caught up and was leading the sort of life you’d expect ‘normal’ children to lead.
It was put to her by the interviewer that infant mortality statistics had not changed, so how could she justify her desire (as if it were not obvious) for the termination time limit to be reduced. What she said, and I’m doing this from memory, was, I think, very telling. She first of all suggested that we need to be a bit careful with statistics. She reiterated the point that children can survive at an age lower than the termination limit. She rounded this off by suggesting that while the statistics may not have changed significantly, for a child who may survive being born very prematurely the issue is very significant indeed.
I think she has a point. And this whole issue reminds me of just how easily we over-rely on the science and statistics. And examples of this, I think, are legion in the medical field.
For example, I have written before about the placebo response and its power in promoting healing. Some (for instance, academics who never go near real patients) dismiss the placebo response as an artefact, and something that is not ‘real’ like the effect you get with, say, a drug that has been ‘proven’ to be effective. My opinion is that if a treatment or approach helps someone, the mechanism behind the improvement is far less important than the fact that they have improved. But I suppose that’s one of the differences between academics and individuals who actually see patients with real problems and who are focused on actually helping people.
Another way science may not be of service of us concerns ‘statistical significance’. This tells us, supposedly, whether there’s some real effect or change going on, or it’s merely something that’s most likely to be due to chance. Statistical significance in scientific studies is denoted by what is known as the P (or probability) value. A value of less than 0.05 is generally regarded as denoting ‘statistical significance’.
Sounds fine so far. Except, I do feel compelled to point out that the choice of 0.05 as a cut-off is utterly arbitrary. It’s a value that the scientific community agree on. It’s a consensus ” it’s not carved in stone like some irrefutable scientific truth. If the scientific community decided that 0.01 was going to be a cut-off, then less things would be ‘statistically significant’. If the limit was set at 0.1 then many more things would be deemed significant. When we understand this, we begin to see just how arbitrary a lot of scientific ‘findings’ really are.
An example of where statistical significance appears to have got in the way of a constructive debate on the subject is vaccination. Our Government here in the UK, most doctors (I suspect) and many commentators would have us believe that vaccination, including the measles, mumps and rubella vaccination (MMR) is ‘safe’. Many will not even entertain the thought that there may be a problem with MMR. They’ll quote the science (some of which is not of the highest quality anyway) in a way that gives the impression, very often, that there is NOTHING AT ALL to worry about.
An analogy may be useful here. Let’s imagine someone decided to do a big study on road safety. Let’s say they counted up the number of times someone, somewhere, crossed the road. And now, let’s imagine, they also count up the number of times someone gets run over (and hurt or killed) as a result of crossing the road. Now, I’m writing this on a plane and can’t even check if these statistics exist. But I think it’s reasonable to assume, that compared to the total number of road crossings, the number of people being knocked down is likely to be very small indeed.
Now imagine we applied some statistical ‘wizardry’ to this (with that arbitrary P value, remember) It’s not too difficult to imagine that one would turn up a result which shows: ‘crossing the road is not associated with a statistically significant increased risk of getting run over.’ Now, many doctors and scientists would interpret this finding as evidence that crossing the road is ‘safe’. However, we all know that while most of the time it is, sometimes it’s not.
Now, getting run over has obvious after effects. Vaccination, on the other hand, may not. The effect, for instance, may be delayed. And also the changes can be more subtle than a broken leg, a ruptured spleen or death. Nevertheless, despite the protestations of some, there is a considerable body of people out there who believe (rightly or wrongly) that their child has been damaged by vaccination. And all too often these individuals are dismissed or patronised.
To get some indication of how some of these parents might feel, imagine for a moment turning up at hospital with your child who has been run over. When you get to casualty the attending doctor asks what happened to your child. You reply that they were run over crossing the road. Now imagine the doctor turns round to you and says with a somewhat withering tone: I don’t think so: Study after study shows that there’s no credible evidence that crossing the road can be harmful to human health.�
Whatever scientists and doctors sometimes contend, the fact remains: accidents can happen.
As usual – just excellent – thank you John!
Dear Dr Briffa,
This is an excellent article that highlights not only the issues of statistics in medicine but also in using them in general. To use a similar example as the babies being born prematurely, they may only have a small chance of survival, but as pointed out, it is literally a matter of life and death so incredibly significant.
I note here that you didn’t give your personal opinion either way – and whilst this article is excellent it isn’t too telling. Do you personally believe the abortion limit should change?
re: MMR and other regular vaccinations/immunisations: these are good for the population but not necessarily good for the individual.
Many practitioners work using population ‘events’, eg. I have a tummy upset, Oh yes there is a lot of this going around, have some ‘X’ that will clear it up! This is on the basis of ‘common ailments occur commonly and uncommon ailments occur rarely’. The really smart practitioner will be very, very aware of the limitations of such approaches.
Or again as one Dr put it to me, when I consulted about a chest infection, It wont be TB, we’ve had our four cases in this area already this year! To this day I do not know if this was said with tongue in cheek….but I do hope it was.
I think the limit for termination should have been set at the time in gestation when it can be proven that a child has survived outside the womb, and has managed,with a initial period of assistance if necessary,to maintain its own breathing, heart and other vital organ functions for a period of time determined by the medical scientific community, with oversite by legal personnel and lay people.The period of time when assistance can be given should also be determined by the medical scientific community, with oversight by legal personnel and lay people.
Gary
This blog post isn’t really about abortion time limits, it’s about the limitations of the scientific method. My personal opinion on the time limits for abortion (which, by the way, is quite uninformed) isn’t really relevant to the real issue at hand, here.
Need more of this kind of scientific questioning. The use of statistical significance is problematic – all it really tells us is that at a 95% significance if we repeated the study we would get comparable results 95% of the time. It doesn’t tell us if the answer is correct, merely that the results are consistent.
To my way of thinking there is a difference ininterpretation and scientists should be careful to point that out.
Great topic. I’m always annoyed at the way relative and absolute risk percentages are used in the media. Most people don’t understand those, either. Another post topic?
yes totally agree
“science”.. statistics.. are black and white
life is grey, a vague misty kind of grey
Thank you for this.. It is not just about abortion of course, it is about what constitues “objective” measures; you have here helped to demonstrate a clear and insightful way to convey the blanket use/misuse of probability in statistics in medicine. While those subcsribing to your blog “get” the misuse of statistics, the road accident scenario made it much more immedate. I shall use this analogy to further the questioning of the status quo by my friends… Neat. Cars, road accidents, ubiquitious understanding. Well, perhaps. Thank you for giving me a suggestion to aid understanding from others.
I appreciate the valid comments regarding statistical significance but hope that the unfortunate choice of using the mmr vaccine as an example doesnt fire up dissenters again. Consider the ‘significance’ of the rise in infant morbidity and mortality if measles becomes endemic in communities again due to lack of uptake of vaccination.
Any vaccine has potential to cause harm, however rare.
The problem with statistical significance tests is that they are answering a different question than what is often assumed. Experiments are usually done to test some hypothesis. Statistical significance essentially answers the question “What is the probability that I would have observed this data GIVEN that a particular hypothesis is true”. In other words, it tells you how well the hypothesis supports the data, not how well the data supports the hypothesis. The proper question is is “What is the probability that the hypothesis is true given that I observed this data” (and you also have to include effects of other background information, such as prior experiments). Not only does this answer the right question, it allows you to do things like compare competing hypotheses. For example, one might find that the lipid hypothesis of CHD is supported at the 90% level; but that doesn’t make it right, just 90% certain. If you test an alternative hypothesis such as “Refined carbohydrates cause CHD” and find it supported at the 98% level, then it’s obviously more desirable (I’m oversimplifying the process, but that’s the basic idea).
Annoyingly, nearly all scientific experiments are interpreted in this backward manner, despite there being a rigorously derived mathematical framework (called Probability Theory) to do it the right way. Edwin Jaynes is the modern father of Probability Theory, and has an excellent (albeit mathematically dense) book on the topic, called Probability Theory: The Logic of Science. It’s not an easy read, but worthwhile.
Your analysis of the statistics reminds me of the American weather reports where they say things like “There’s a 30% chance of rain”.
Whatever the percentage, if it rains you get wet.
Which shows the limitations of statistics.
The real power of the Probability Theory approach is that when combined with Information Theory allows you to do logical reasoning in the face incomplete information. The limitations of what you know become clear, especially when trying to make decisions. This is important in a number of places, not the least of which making medical treatment decisions.
“30% chance of rain” simply tells you the degree of belief about a future outcome. How that affects your decisions has to do with how much you care about whether or not you get wet.
Sometimes people are right for the wrong reason, sometimes they are wrong for the right reason, you have managed to be wrong for the wrong reason.
Never mind, try again.
Oh I’ve just realised you have a book published, ghost writen was it?
Hi Dr Briffa,
I am intrigued by your criticism of academics dismissal of the placebo effect in medical trials. I would be surprised if any academics really question the efficacy of the placebo effect in certain cases as it has been well documented.
It is quite obvious that handing out sugar pills to patients instead of pills containing active ingredients (and therefore inevitably side effects) is safer and cheaper in these cases. The reason this is not done in practice is ethics rather than science. It is not considered ethical to give a patient a pill and lie to them about its content. Whether these ethical guidelines are correct or not is a grey area, but it s not the issue here.
The reason scientist are careful to take into account the placebo effect in medical trials is because they want to specifically test the active ingredients within the drugs. To test the drugs without also testing the placebo effect through double-blind trials would not allow the efficacy of the drug to be measure.
‘Big pharma’ (and the homeopathy industry, not to mention the food supplement industry) would love to be able to include the placebo effect when reporting the results of their latest drugs (when it comes to homeopathy and food supplements they always do include the placebo effect- they would run a mile from a double-blind trial). Drugs with active ingredients which work for one specific illness, for example to counteract hyperactivity, could then be sold for a wide range of illnesses, for example depression, when in actual fact, for depression any placebo would work as well. Bigger market results in bigger profit. Who cares about the side-effects. (Fortunately the only side effect of homeopathy is a significantly reduced bank account!)
Your argument for this to be allowed is based on the idea “well so what? If the placebo effect helps why not?”. The simple answer to this is two fold: sugar pills are cheaper and much less dangerous than prescribing drugs whose active ingredients are not designed for the illness at hand. If it is unethical to give out sugar pills pretending they are real drugs, surely it is unethical to give out real drugs which only work through the placebo effect. If you think it is ethical to give out sugar pills, then give out sugar pills when it will help, again, they are far cheaper and much safer than using actual drugs.
Hope this clears up the reason why academics are so obsessed with eliminating placebo effect when testing drugs, and why alternative or complementary medicine providers aren’t.
Lex
I entirely understand the need of some people to perform randomised, placebo controlled trials (chiefly, in an effort to discern whether what is being tested has a ‘real’ effect or not). However, in the real world (that’s real people, with real problems) the fact that the placebo response may account for a lot of even the whole of a clinical response is not generally important for those the treatment is intended to help (those real people with real problems, again).
Whatever your views regarding the ethics of giving placebos the fact remains that some doctors do give them, and they may benefit to individuals too. I don’t advocate the use of placebos (as you seem to suggest), but the fact that they are used in medical practice is why I have written about this in the past. Also, remember that some placebos are self-administered, so the ‘ethics’ of prescribing them does not come into it.
Also, even if study has found a treatment to be no better than placebo, we actually do not know (for certain) if any benefits gained from this treatment in an individual were due to merely a placebo response, or some real effect, or both. I’d be very wary indeed about extrapolating from science to the individual with the level of certainty many doctors and academics often exhibit.
And all of this is a diversion anyway, seeing as the post was not about the placebo response, but mainly about the relevance of ‘statistical significance’ in the real world. So, whether a treatment is deemed more effective than placebo is determined by the application of arbitrarily set criteria. Set other criteria, and we get a different ‘result’. Now, suddenly, the world of science-ology does not seem as objective as many scientists and academics would have us believe it to be.
You tell us that ‘they’ (whoever ‘they’ are) in homeopathy and food supplements would ‘run a mile from a double-blind trial’. I can’t speak for homeopathy (as I don’t know much about it), but you are simply incorrect with regard to double-blind studies on nutritional agents. There is, in fact, quite a body of evidence regarding the effects of nutritional agents on health that is double-blind in nature. Here’s a recent study as an example: Su KP, et al. Omega-3 Fatty Acids for Major Depressive Disorder During Pregnancy: Results From a Randomized, Double-Blind, Placebo-Controlled Trial. J Clin Psychiatry, 2008 Mar 18 [Epub ahead of print].
Now, either you didn’t look for the presence of such research or you just assumed it did not exist. Or maybe, you looked, found there was some evidence and decided just to ignore it all the same. It’s just this sort of subjectivity (and apparent bias and prejudice) in science that I think needs to be exposed.
If you have any views on the arbitrary nature of ‘statistical significance’ I’d be pleased to hear them….
Derrik
Oh do please tell us why I’ve got it wrong for the wrong reason, or are we just to take your word for it?
And what’s that too – some wild speculation about whether I write my own books for not (like that’s got anything to do with it anyway….).
Indulge me in some idle speculation of my own. I see from the information that comes with the IP address of your computer that you have a connection with one of England’s ‘finest’ seats of learning. Maybe you are an academic yourself?
Perhaps you could tell us? And while you’re at it, why not reveal your identity, and let us all see who it is that makes assertions that he/she does not feel the need to substantiate in any way whatsoever….
Dr Briffa,
I read your post with interest, after my attention had been drawn to it by another blogger, and I thought I’d ask a couple of questions of you / share a couple of views with you.
Of your section on statistical significance and p-values, one person has pointed out: ‘that’s all true, although the fact that p<0.05 is a totally arbitrary choice isn’t exactly a secret. We all know it. Often, people will demand p<0.001. That’s why we quote p values rather than just printing “yes” or “no”’.
Having read the two blog posts, it seems to me that you are trying to imply (unfairly) that, because the usual p-value of 0.05 was reached by consensus, p-values and statistical significance are somehow meaningless and scientific findings themselves are therefore arbitrary. This seems like the perfect excuse for someone who wishes to recommend treatments, supplements or diets that are not backed by scientific evidence. Also, your post makes it seem as if scientists are somehow slapdash when it comes to use of statistical methods – like the scientists have shrugged their shoulders and said ‘p-value? let’s just make it 0.05′. You ignore the efforts made by scientists to take account of certain factors when completing research – one example being the use of Bonferroni correction when testing more than one hypothesis on a set of data.
Unfortunately, a policy of ignoring scientific evidence leads us down a somewhat depressing path – we go from having a ‘workable-but-imperfect’ system for discovering truth to… having no system at all. Without having the scientific method available for us to use, surely any one anecdote is as good as any other anecdote? And any single anecdote may be used to justify, well ” just about anything.
Worryingly, you show us some examples of this approach elsewhere in your blog post. You seem to imply that the experience of one mother, rather than a properly conducted study such as Epicure, should inform abortion policy in this country. You then go on to deny that the MMR vaccine is safe, and use an analogy about road accidents in order to make your point. While it is theoretically possible that the vaccine may cause autism, there is currently no good reason to think that it does. There are real risks with vaccines – such as the possibility of an allergic reaction – and those groups considered to be most at risk from vaccines are advised not to get jabbed. For more on the risks of the MMR vaccine and the risks of the diseases the vaccine prevents, try http://www.mmrthefacts.nhs.uk/library/sideeffects.php – frankly, the “MMR – The facts” page will be of far more use to parents worried about MMR than anything you have written on the subject Dr Briffa.
jdc
Just one more thing: “You tell us that ‘they’ (whoever ‘they’ are) in homeopathy and food supplements would ‘run a mile from a double-blind trial’. I can’t speak for homeopathy (as I don’t know much about it), but you are simply incorrect with regard to double-blind studies on nutritional agents.”
Mmm. You’ve cited just the one double-blind study to refute the accusation that the supplement industry would ‘run a mile’ from a double-blind trial. I still think that the accusation stands. Most food supplement companies don’t conduct scientific trials of their products at all – and why should they? After all, they aren’t required by regulation to do so and if they took the chance and conducted a study, then the results might well be ‘not to their liking’ and the money they have spent on this scientific study would be considered (at least by the finance dept!) to have been wasted. Other supplement companies give their product to schools in order to promote this initiative as a ‘trial’. Still others are stated to have approached researchers but insisted on retaining control of the data. What ethical scientist could abide by such terms? So, while there may well be some double-blind studies of nutrients, your commenter Lex still makes an excellent point regarding the general state of affairs in terms of supplement companies conducting proper research. As for homeopathy firms, I’ve seen some info on Boiron and apparently they spend 18.5 times as much on marketing as they do on R&D.
Of course, these tricks aren’t exclusive to homeopathic and food supplement companies – ‘Big Pharma’ spends twice as much on marketing as on R&D and has form when it comes to burying studies or cherry-picking the ones they want to submit. But let’s leave the readers of this blog under no illusions – homeopathy firms and food supplement companies are in business and they act like businesses in protecting themselves rather than the consumer. Protection of the consumer is generally undertaken by government and by executive agencies of the government. We have to rely on the MHRA, ASA, FSA and Trading Standards to protect us because Big Pharma, Homeopathy and Nutritionism won’t.
jdc
jdc – in response to post no. 18
You’re right, the arbitrary nature of p-values is not a ‘secret’, but you’d be surprised just how much this fact is not fully understood or appreciated by those with no scientific training (like the majority of the readers of my site, I suspect). So, nothing wrong with pointing that out, I reckon.
I didn’t state not even imply that scientists are ‘slapdash’ in the application of p-values, merely that what p-value is chosen is arbitrary in nature, which means that what is viewed as ‘significant’ is also quite arbitrary.
What I think happens in the real world is that when a scientific study pronounces a finding that is said to be ‘statistically significant’ or not, is that people interpret that to mean that a drug works or doesn’t or a vaccine is safe or not. And what I’m saying (if this wasn’t absolutely clear in the post) is it’s not like that: because the cut-off for what we determine to be ‘significant’ is arbitrarily set. This may be obvious to you. But as I pointed out above, I actually don’t think it’s obvious to everyone.
The road accident injury analogy was used in an attempt to provide a graphic example of how science and P-values may pronounce something to be safe – safe, perhaps from the standpoint of an arbitrarily set criterion, but not safe and possibly deadly for the person who gets run over.
You also appear to misrepresent me in suggesting that I have the opinion that science has no value. I don’t hold that view at all, and you would know if you spent just a few minutes trawling my site: it regularly cites scientific evidence.
However, science has considerable limitations (something that some scientists and academics are loathe to admit, it seems), and we must be aware of these limitations if we are to interpret science properly. So, for the record, I support the concept of science, but I’m no slave to it.
And I also know that one’s experience in practice (in the real world, with real people with their real problems) is important too. It’s not just me that thinks this: evidence-based medicine is described in a seminal editorial of the subject in the BMJ as: ‘…about integrating individual clinical expertise and the best external evidence.’ See: http://www.bmj.com/cgi/content/full/312/7023/71
So, jdc, perhaps you’d like to share with us some of you clinical expertise. Or is healthcare, for you, an essentially ‘academic’ pursuit? Perhaps you can tell us….
And so to MMR…
First of all, you suggest that I believe MMR to be unsafe. Actually, I said no such thing. My point is, we can’t be sure that it is safe. Those two positions are not the same.
Anyway, on to the ‘evidence’ that you refer to that we should, apparently, take comfort in. In the link you supplied under ‘How do we know that MMR is safe?’, we are informed that:
….there is a great deal of evidence to suggest that the vaccine is safe.
* The MMR vaccine is used in over 90 countries, including the whole of the European Union, Australia, New Zealand and the USA
* Over 500 million doses have already been given worldwide
* In the USA, the MMR vaccine has been given to children for nearly 30 years
* Long term research conducted in Finland has reported that no deaths or permanent damage has ever been linked to the MMR vaccine
* The World Health Organization (WHO) describes the MMR vaccine as a ‘highly effective vaccine which has an outstanding safety record’
There is a risk that if large numbers of children do not have MMR, the diseases the vaccine prevents will come back.
Let’s have a look at this ‘cast iron’ advice in just a little depth:
The first three bullet points tell us how widely and for how long it has been used (this is no different from saying ‘billions of people have crossed roads over the past 50 years’ ” it tells us NOTHING AT ALL about safety – NOTHING).
One other bullet point refers to long-term research in Finland, but does not reference this, for some reason. I suspect what is being referred to here is the research that formed the basis for the following letter:
Peltola H, et al. No evidence for measles, mumps, and rubella vaccine-associated inflammatory bowel disease or autism in a 14-year prospective study. Lancet 351(9112);1327-8. This letter was based on data that came from a previous study by the same team: Peltola H, et al. The elimination of indigenous measles, mumps, and rubella from Finland by a 12-year, two-dose vaccination program. N Engl J Med. 1994 331(21):1397-402.
This study seems to have been used as evidence for a lack of link between MMR and autism because it apparently showed NO cases of autism after millions of MMR administrations. The devil of course, is in the detail: autism cases were NOT MONITORED as part of this. Some other adverse effects were monitored, it seems, but not autism (for some reason). In fact, in the whole of this study, the words ‘autism’ appears precisely NO times.
It is quite shocking to me (and perhaps some other people reading this) that this evidence has used by some to conclude that MMR does not cause autism, when it is completely inadequate from a scientific standpoint. Some would say it is actually ‘fraudulent’ to use this science in an effort to ‘persuade’ the unsuspecting public that MMR does not cause autism.
So, let’s just hope that the WHO is not relying on this sort of ‘evidence’ when it pronounces MMR to have an ‘outstanding safety record’ (though I very much suspect it is).
And then all this is rounded off with the usual clarion call: “There is a risk that if large numbers of children do not have MMR, the diseases the vaccine prevents will come back.” Though quite what that has to do with the safety of MMR is anyone’s guess.
So, jdc, you have drawn our attention to this ‘MMR ” the facts’ site, and now perhaps you’d also like to comment on the robustness of the ‘evidence’ this site uses to pronounce MMR as safe, specifically with regard to autism (by the way, it was you that raised the autism issue, not I). Please do tell us what you think of the Peltola study in particular (the one which didn’t even gather data on autism). This is an honest request, please do let us know your views.
You say there is no ‘evidence’ that MMR causes autism. Well, I don’t know if MMR can cause autism or not. But, personally, I am loathe to dismiss the ‘evidence’ that comes in the form of countless parents who say that their child was developing normally, until they had MMR vaccination shortly after which they regressed into an autistic state.
And one other thing that may interest you (or other readers of this) is that the US Government recently conceded (out of court) that a child’s (Hannah Poling) autistic state had been significantly contributed to by vaccines she had as a toddler. This child actually had 5 vaccinations (a total of 9 vaccine components) in a single day. However, it’s not too difficult to imagine how a smaller vaccine load could still lead to problems in susceptible children.
jdc – in response to post no. 19
Lex wrote ‘they would run a mile from a double-blind trial’. This is stated in absolute terms, no? Lex did not use words such as ‘generally’, or ‘usually’ or ‘tend to’. No, they ” all of them ” would not engage in double-blind research is the assertion.
Now, as I said, there is a significant body of double-blind research in the area (some of which is industry-funded, of course). I actually started out with a list of studies to rebut Lex’s claim. But then I remembered something I think Karl Popper said about swans: If the hypothesis is that there are only white swans, I only need to show the existence of one black swan (not two, or 10 or 100) to disprove the hypothesis.
And then I wondered if someone with a very pro-science stance would ‘take the bait’, focus on the fact that I only presented one study, and in so doing would betray ‘good science’ (and even logic) and demonstrate the subjectivity and prejudice that is so often found in science and academia.
In partial reply to jdc’s various comments:- the website known as “mmrthefacts” is regarded by parents of “allegedly” vaccine-damaged autistic children with considerable disdain. At one point it recommended that a child who had reacted badly to the first MMR should be given the so-called booster MMR regardless of its prior adverse vaccination reaction. Surely this goes against commonsense as well as good medical practice?
The example I always use is that penicillin has been a great boon to mankind but my doctor has warned me that the next time I receive it could prove fatal (he wasn’t joking). My Medicalert medallion is in my purse.
The attitude “one size fits all” fails to take any notice of individual susceptibilities (see previous paragraph) and there is considerable evidence from the parents of autistic children that autoimmune disorders, allergies and gastrointestinal disorders appear with alarming frequency in the family medical histories of children who’ve descended into regressive autism following vaccination. Why isn’t this being investigated?
One thing that really worries me is the lack of intellectual curiosity in the orthodox medical profession – they’re being told about adverse vaccination reactions by parents of autistic children and yet no-one seems to think this should be investigated. I think we’re all aware that very few adverse vaccination reactions are notified via the “yellow card” system. Where are the U.K. research studies involving clinical examinations of allegedly vaccine-damaged children?
On a personal note I can inform jdc that, having had boy/girl twins and watching my normally developing daughter descend into regressive* autism immediately following MMR, there can be no doubt that something happened. The point when doctors go quiet and then hurriedly change the subject is when I point this out and then say “we’ve got dated camcorder footage”.
* Loss of eye contact, total loss of developing speech (mute for two years), appeared not to understand what was being said to her, etc. etc.
Your comments about 95% confidence limits and the analogy to road crossing casualties are not correct I’m afraid .
Statistics and the commonly accepted p=0.05 criterion is used to demonstrate CAUSE & EFFECT, not absolute numbers or relative risk ie the chance of being run over in your example, which is what you are talking about in your comment if you get run over then for sure its 100% as far as you are concerned.
95% confidence limits are an arbitary limit agreed, but its a bench mark, (although you can use p=0.1, but obviously with a lower level of confidence that the hypothesis is correct)
So you use confidence limits, in your analogy of roads to demonstrate the effect of different road surfaces, lighting, speed limits etc etc & determine which was most effective at reducing casualties.
Your last comment refers to incidence & risk, thewhole MMR/autism debate is around cause & effect and epidemiological studies on vaccinated v unvaccinated populations or if the autism rate dropped when vaccination policy changed.
Occam
Yes, you can use probability values to assess different road conditions to, as you suggest, assess which is the most effective at reducing casualties, but you can also use them when assessing what effect ‘crossing roads’ or ‘not crossing roads’ has on risk of casualty, and if one of these factors carries a ‘statistically significant’ enhanced risk of casualty compared to the other.
With regard to MMR, you refer to epidemiological studies. My point is that these are simply inadequate for ‘proving’ that MMR is ‘safe’, and also tell us nothing about ‘cause and effect’. So, thank you for drawing our attention again to this.
Your comment on crossing roads says “assess the risk” exactely my point of course, you can calculate a rik of doing this and of course there will be a highly significant difference statistically in the risk of death if you cross the road compared to not crossing the road, so what’s your point?
MMR unfortunately as you will know you cannot prove a negative, ie that there is not any harm, but you can test whether there is harm statistically between the two populations, that’s the whole point testing the null hypothesis that there is a difference (ie harm) at the p=0.05 level. I stand to be corrected but I believe that this has not been demonstrated in epidemiological studies of MMR vaccination
Occam – in response to comment no. 25
You state that: ‘of course there will be a highly significant difference statistically in the risk of death when you cross the road compared to not crossing the road.’ Can I ask how you KNOW this? What about if people are run over and killed while standing on or walking along the pavement? What about people suffering ‘death’ from other causes?
I suggest that your assumption is a bit hasty, and also that it’s not very ‘scientific’ to predict with certainty the results of studies that haven’t even been done (as you have done). But this isn’t the first time a commenter here who is a congregant of the church of science-ology has exhibited some distinctly unscientific thinking (see comments 19 and 21 for another example).
The reality is that it is entirely possible that a ‘scientific’ study will find no statistically significant enhanced risk of death with crossing the road compared to not crossing the road. And studies that find MMR vaccination is not ‘statistically significantly’ associated with some adverse effect do not prove that MMR cannot cause that adverse effect. THAT’S my point.
And with regard to proof of some problem (e.g. autism) with MMR, you’re obviously right: you can’t prove a negative. But you wouldn’t necessarily know that from the people who have used epidemiological evidence to insist that MMR does not cause autism. Again, I feel compelled to thank you again for drawing our attention to the inadequacy of the evidence used to ‘persuade’ us MMR is safe.
Your comments here serve quite elegantly, I think, to highlight some of the inadequacies of the scientific method (which was the aim of the original post), not to mention the distinctly unscientific approach some take in the name of science.
You’re wriggling, you would control & test that there was no significant difference from other causes of death, ie knocked down on the pavement between the control & experimental groups, the factor being tested for is the act of crossing the road, a properly controlled study, as in clinical trials, would ensure there were not confounding issues, look at the published epidemiological breakdown by race, age, sex etc etc in clinical trial reports comparing test and comparator drugs.
Again you wriggle re autism the conclusion has been drawn that there is no evidence that there is a causal relationship between MMR & autism, ie the null hypothesis that there is harm was not demonstrated.
Occam – in response to comment no. 27
Fine by all means control as much as you like, but you didn’t answer the question: How is it that you managed to predict with certainty the result of a study that hasn’t been done? I’m hoping the irony of you accusing ME of ‘wriggling’ is not lost on you, though I suspect it might be.
And with regard to MMR, please do tell us all how it that I’m ‘wriggling’ here: As I have stated quite clearly, my position is not that MMR causes autism, only that it has not been proven NOT to cause autism.
And another little ‘scientific’ point that seems perhaps to have passed you by: the epidemiological evidence use to vindicate MMR could never prove (or disprove) a CAUSAL relationship between MMR and autism. But I suppose that doesn’t matter much to those who have made their mind up before the ‘facts’ are in (you know, those distinctly unscientific scientists I referred to in my last comment…)
Dr B,
Your road-crossing analogy has got a lot of people’s backs up. I feel I must correct one implicit point:
Significance testing if performed correctly* has nothing to do with how rare an event is. This was a bad point to start on and it has distracted from your essential and correct point that even rare events can happen and their consequences can be devastating to those involved.
We have lots of roads and sadly lots of road accidents so there will no doubt be lots of data. I actually think that a well-performed* study would find that crossing the road WOULD be associated with a statistically significant increased risk of getting run over (at whatever level of confidence/chosen p-value).
And by the way I obviously cannot use that information to assess what anyone in particular chances of getting across a road intact actually are. I don’t think anyone would disagree with that. (I don’t think you and Occam actually disagree).
*It’s a big “if”. In short p-values only work properly if studies have enough data points that the rare event can kinda be spotted a few times and separated out from randomness if you like (you yourself have pointed studies out where this hasn’t occurred before I believe). The statistics around low number studies get very weird indeed.
Cynic
You say: “In short p-values only work properly if studies have enough data points that the rare event can kinda be spotted a few times and separated out from randomness if you like..”
But what if study isn’t large enough (i.e. there are not enough data points) and/or something is too rare to ‘spot’, what then?
You (as did Occam) maintain that a study on road crossing and death/injury/whatever would produce a statistically significant result. And in so doing you seem to have, like Occam, developed magical clairvoyant abilities. It’s a neat trick, but not very scientific, if I may say (do excuse me if I’m repeating myself).
Now, even if the analogy of road-crossing doesn’t work for some and has even ‘got some people’s backs up’, can I ask why that’s REALLY important? Because, before we allow ourselves to stray too far from the real issue at hand, the point is that the epidemiological studies used to ‘prove’ MMR does not cause autism have done no such thing. And never will they. I don’t dismiss epidemiological evidence out of hand, but as we all should know, they can never be used to prove (or disprove) that MMR can cause autism.
If only we had had some PROBABILITY STUDIES on WMD and the time it takes to load (from storage..think what this really means) them, perhaps we would not be taxed quite so heavily now!
My initial comment still stands: immunisation/vaccination is good for the population, but not necesaarily good for the individual. Thus with diphtheria, more of the population might die of infection without immunisation than would die if the population was immunised. Single blind time dependent population studies do demonstrate that this is the case; but from what others have told me, I’m glad I havent had a damaged child from diphtheria immunisation.
RE: statistics etc.discussed;we all need to remember that stats profile a POPULATION, not individuals. and the Pvalues are probabiities NOT necessarily certainties!!
THE POPULATION needs more of these discussions to try and get more people to understand what “the figures” mean. If I could make it really interesting, I would teach it in schools and it would be on the GCSE maths syllabus – and before someone says it is taught, It would seem from these discussions that not many understand it; and then we have the conudrum,badly taught or mental inability to understand?
Peter
If the flimsy, unscientific, biased and sometimes irrelevant arguments put forward here (by people I think would describe themselves as ‘scientists’) are anything to go by, I suggest that the issue of scientific illiteracy is mainly a problem of how science is taught, and not so much an issue of comprehension.
I wish the aims of those in the field were as laudable as yours, I really do. Because I reckon that not everyone in the field of science actually wants members of the public to understand science, because if they did, it would be a whole lot harder to ‘persuade’ the public of things that have no basis in truth or fact, but are rooted in some ideological, political or commercial agenda.
If there’s not enough data points then surely, we simply cannot say either way. The scientific thing to do, you must agree, would be to investigate further and seek out more data?
Or how else can we hope to move forward from that point?
I am not familiar with but imagine evidence of MMR/autism link is pretty complicated and not clear-cut at all. However in my view your overly-simplified and hyperbolic road-crossing example does no one any favours. Within this example though you have also definitely given the impression that if something is a rare event then any kind of statistical tools used to examine it cannot be trusted. This technical point is not true and was all I was seeking to correct. I notice you did not engage with that point at all.
We should of course always be very cautious when using statistics. They can be very useful if used properly so maybe we should try and encourage better use of them rather than making them the bad guy?
I of course agree that epidemiological evidence cannot prove or disprove any causal relationships.
Cynic
“If there’s not enough data points then surely, we simply cannot say either way. The scientific thing to do, you must agree, would be to investigate further and seek out more data?”
Yes, I agree entirely. I genuinely would like to credit you for your reasoned, reasonable and ‘scientitfic’ (truly) approach. And in the case of MMR and autism it seems to me that further study is needed. What I’d like to see less of, personally, is scientists and politicians insisting and bullying people into believing something that they do not know to be true.
“Within this example though you have also definitely given the impression that if something is a rare event then any kind of statistical tools used to examine it cannot be trusted. This technical point is not true and was all I was seeking to correct. I notice you did not engage with that point at all.”
I didn’t state or even imply, I think, that NO type of statistical tool can be ‘trusted’. The original post was an attempt to explore the limitation of ‘statistical significance’, and its arbitrary nature. We can trust statistics if we want (I refer to them regularly on this site…), but I do think we should be upfront and honest about their limitations too.
“I of course agree that epidemiological evidence cannot prove or disprove any causal relationships.”
Agreed. Now tell that to the scientists who cite epidemiological evidence as ‘proof’ that MMR does not cause autism.
Now tell that to the scientists who cite epidemiological evidence as ‘proof’ that MMR does not cause autism.
Epidemiological evidence is not the only evidence that has shown no evidence for an association between MMR vaccine and autism. There are virological studies which also undermine the hypothesis, as well as testimony from one of Wakefield’s team that Wakefield’s study suffered from false positives (which he allegedly knew about).
I could claim that diabetes is caused by MMR vaccine, and would be able to defend my claim on the same basis you defend the autism-MMR vaccine hypothesis. i.e. You have no evidence disproving my claim.
Of course, the careful reader will notice that I gave no evidence for my claim, which is effectively what Wakefield did at his press conference.
Anthony
“Epidemiological evidence is not the only evidence that has shown no evidence for an association between MMR vaccine and autism. There are virological studies which also undermine the hypothesis, as well as testimony from one of Wakefield’s team that Wakefield’s study suffered from false positives (which he allegedly knew about).”
I note you suggest this evidence ‘undermines’ the hypothesis, but you seem to have stopped short of saying it ‘disproves’ it. Perhaps you can clarify?
Also, who said anything about Andrew Wakefield? Specifically, who says it’s only his putative mechanism that could be behind the putative link between MMR and autism? Maybe some other mechanism is at play, no? Let’s be methodical about this, I suggest, and not limit ourselves to one possibility.
So, even if there is evidence that ‘undermines’ Andrew Wakefield’s theory, that in no way disproves the hypothesis that ‘MMR can cause autism’.
“I could claim that diabetes is caused by MMR vaccine, and would be able to defend my claim on the same basis you defend the autism-MMR vaccine hypothesis. i.e. You have no evidence disproving my claim.”
Agreed, except where, Anthony, does it look to you that I claimed that ‘autism is caused by the MMR vaccine’? Or are you referring to someone else’s assertion?
There is another aspect to NMR immunisation that I have never seen/heard anyone mention. And that is the adjuvanrt effect of one “active principle” on the other two “actrive principles”. For this reason alone, if I had to have children immunised I would insist on separate N,M and R and they would given separated by about 14days, by which time immediate imflammatory reactions would have subsided.
Elizabeth, I think your point about lack of intellectual curiosity about MMR is underlined by Angela Howe’s comment: “I hope that the unfortunate choice of using the mmr vaccine as an example doesnt fire up dissenters again.”
If anyone raises doubts about the safety of the MMR vaccine they are dismissed as irresponsible for expressing views that might dissuade parents from giving the vaccine, and therefore putting lives at risk. If the medical profession were so sure of their ground they would welcome further research in this area .
I was referring to Wakefield’s assertions, repeated by others. And which you have a post about entitled “Why the MMR-autism ‘war’ is far from over” and state:
Distinctly shoddy science?
Having your cake and eating it is a neat trick, which few succeed at.
Anthony
“I was referring to Wakefield’s assertions, repeated by others. And which you have a post about entitled “Why the MMR-autism ‘war’ is far from over”…
Let me see, does that mean because I write about someone that I must automatically share their views and beliefs? Or are you simply going to ‘autoresponse’ mode and suggesting that anyone who questions the safety of MMR (me) believes MMR is unsafe. Where is the logic in either of these stances? Or maybe you had something else in mind. Please do clarify.
“Distinctly shoddy science?
Having your cake and eating it is a neat trick, which few succeed at.”
I have claimed that the science used to claim or ‘prove’ MMR causes autism is shoddy. If you’d like to refute that, go ahead.
But please do tell us Anthony, how is it that I’m having my cake and eating it? That’s a genuine question, so please don’t ignore it (see below)?
A couple more questions if I may:
In a previous comment I asked:
“I note you suggest this evidence ‘undermines’ the hypothesis, but you seem to have stopped short of saying it ‘disproves’ it. Perhaps you can clarify?”
You did not reply. Why, and would you care to do so now?
I also suggested that if whatever evidence you have ‘undermines’ Andrew Wakefield’s theory, that in no way disproves the hypothesis that ‘MMR can cause autism’. I thought you’d like to engage with this point but you haven’t. I’m asking you to do so now.
I don’t think anyone really does that — I’ve never seen anyone take that stance. It’s something of a straw-man. Sure I imagine a few people do that, but that’s not the main pro-MMR viewpoint, and arguing against those people without acknowledging that most pro- as well as anti-MMR groups both disagree with them is reckless and irresponsible in a debate where people are actually dying of preventable diseases because they’ve been lied to and told that the prevention causes autism.
Andrew
You’re joking, right? Check out the UK Government’s very own summary of the ‘evidence’ that MMR is safe that jdc very kindly drew our attention to in comment 18 that I presented (along with a critique) in comment number 20: 5 bullets points, one refers to ‘science’ (if you can all it that) and it was entirely epidemiological in nature. Now, do you think the job of writing the ‘How do we know MMR is safe’ page of the “MMR ” the facts’ website for the Government was given to scientists, (or perhaps just farmed out to the teaboy)?
And that’s a joke about me being ‘reckless and irresponsible’, no? Tell me how it’s reckless and irresponsible to point out that we don’t know if MMR causes autism, and perhaps have the temerity to suggest more work needs to be done. Imagine, if you will, a scenario where it turns out that MMR can cause autism. Do you think it will be viewed that our politicians and some scientists acted responsibly in dragging their heels on this, constantly insisting that MMR does not cause autism despite this not being established as fact? And do you think that those who called and pressed for appropriate research to be done will be labelled ‘reckless’? It’s a strange old World some of you scientists seem to inhabit, I reckon.
Anthony and Andrew
I forgot to mention something: While I clearly don’t see eye-to-eye with you, I do genuinely respect your willingness to be transparent regarding to your identities. Personally, I’d like to see a bit more of that here and elsewhere.
John,
Let’s set out your original comment:
It is your claim that such research is shoddy. Without knowing your criticisms, I cannot refute them. To come to such a conclusion you must have read and found substantial scientific failings in those studies. It should therefore be a relatively simple task to document the individual failings of each study on your blog. So far, your major criticism is a more diffuse criticism that some of the research is epidemiological in nature, which does not deal with the non-epidemiological studies.
Given the dangers that parents expose their children to by non-vaccination, claims such as these should be substantiated. Yours views are no doubt respected by people making decisions about their children and vaccines.
There’s also an implication in the above quote that such studies were performed to silence critics. Do you consider this was part of some concerted and organised campaign? Would it have been better if they had not be performed?
I believe this post, and its follow-up post, can be construed as suggesting that doubt exists over the safety of MMR vaccine in relation to autism. It is being taken as such by the members of the JABS forum. Your, arguably technically correct, stance that you are merely pointing out that MMR vaccine has not been not proved to be causing autism is a possible get-out-of-jail-free card. However, for reasons I will outline later it is a weak defense.
Wakefield put forward a hypothesis that MMR vaccine caused autism. The Autism-MMR vaccine hypothesis was not supported even by his initial study, and we have since learned how false positives obtained in his study further undermined it. Other studies have been performed in the ten years since he made his extraordinary claim, none of which have confirmed his hypothesis.
However, no matter how many studies are performed, it is extremely difficult to prove a negative and refute utterly the Autism-MMR vaccine hypothesis. However, the Autism-MMR vaccine hypothesis has taken on the characteristics of Bertrand Russell’s Celestial Teapot.
The following extract is taken from Susser M. The logic of Sir Karl Popper and the practice of epidemiology. Am J Epidemiol 1986;124:711-718, 1986.
Given ten years of failures to affirm the Autism-MMR vaccine hypothesis, and plenty of consistency of null results, it seems reasonable to reject the hypothesis.
Regards
Anthony
“It is your claim that such research is shoddy. Without knowing your criticisms, I cannot refute them. To come to such a conclusion you must have read and found substantial scientific failings in those studies. It should therefore be a relatively simple task to document the individual failings of each study on your blog. So far, your major criticism is a more diffuse criticism that some of the research is epidemiological in nature, which does not deal with the non-epidemiological studies.”
Do you agree that epidemiological evidence cannot be used to prove (or disprove) causality? I’m assuming with your ‘scientist’ hat on for a moment that you’ll simply answer ‘yes’ to this question (but do correct me if I’m wrong here). So, assuming it’s a ‘yes’, are you prepared to accept that no amount of epidemiological evidence, however voluminous, will really tell us if MMR causes autism or not? So, I reckon those that cite epidemiological evidence as ‘evidence’ that MMR does not cause autism are in fact referring to science that is inadequate, not fit for purpose and therefore ‘shoddy’ (shoddy partly because it’s often scientists that quote this stuff and they really ought to know better).
Assuming we’re agreed on this, then all we need to do now is look at those non-epidemiological studies you referred to. Now, let’s assume for a moment I know not of what you speak, and what I’ve been referring when I say ‘shoddy science’ is the epidemiological data.
So, you’re now in a position to show me what an idiot I’ve been all along? Because now you can wheel out all this non-epidemiological stuff you say there is (but to date, have not actually cited).
“Given the dangers that parents expose their children to by non-vaccination, claims such as these should be substantiated. Yours views are no doubt respected by people making decisions about their children and vaccines.”
The only claim I’ve made is that we don’t know whether or not MMR can cause autism. So, again, let’s assume I’m quite ignorant, and know nothing of the research. Now, if you refute my claim (and assert that MMR does NOT cause autism) then it is incumbent on YOU to provide the evidence. I don’t mind being wrong on this. Believe me when I tell you I have very publicly shifted my position on certain issues when new evidence came to light and/or to my attention (e.g. saturated fat). You have the opportunity to enlighten me. Please take it. And if you have full text copies of the studies to give me, even better. Because no doubt at some point you will have read them in their entirety.
But if it turns out that that evidence is not really there, then would it inconvenience you awfully if someone were to go and actually do the relevant work? I mean, if it were to turn out that MMR can cause autism, then all this dragging of heels that seems to have gone on won’t have been helping matters, will it?
“There’s also an implication in the above quote that such studies were performed to silence critics. Do you consider this was part of some concerted and organised campaign? Would it have been better if they had not be performed?”
For the record, I think some politicians, scientists and journalists have done their level best to ‘persuade’ people that MMR does not cause autism, when, it is my contention, they can’t have known that. I actually don’t have an opinion on whether it would have been better if previous studies had not been performed, and frankly this is a diversion. I think what matters is not what has been done, but what we do now.
“I believe this post, and its follow-up post, can be construed as suggesting that doubt exists over the safety of MMR vaccine in relation to autism. It is being taken as such by the members of the JABS forum.”
Without the appropriate evidence that demonstrates MMR to be safe, I don’t think it’s too much of a stretch to imagine that in some people’s mind (including my own) there is ‘doubt’ about the safety of MMR with respect to autism. Why, does it seem to you that this is in any way a contentious point (it’s blindingly obvious).
“Your, arguably technically correct, stance that you are merely pointing out that MMR vaccine has not been not proved to be causing autism is a possible get-out-of-jail-free card. However, for reasons I will outline later it is a weak defense.”
I’m ‘technically correct’ but my ‘defense’ is ‘weak’. You’ve got this the wrong way round again: my claim is we don’t know whether or not MMR can cause autism (that’s where I’m technically correct, right?). So if your position is that I’m wrong on this, it’s up to you to ‘defend’ your position with the appropriate science.
“Wakefield put forward a hypothesis that MMR vaccine caused autism. The Autism-MMR vaccine hypothesis was not supported even by his initial study, and we have since learned how false positives obtained in his study further undermined it. Other studies have been performed in the ten years since he made his extraordinary claim, none of which have confirmed his hypothesis.”
So, can I summarise, and say that Wakefield’s theory has NOT been disproven. Because, if it had been, you’d have said so, right?
“However, no matter how many studies are performed, it is extremely difficult to prove a negative and refute utterly the Autism-MMR vaccine hypothesis. However, the Autism-MMR vaccine hypothesis has taken on the characteristics of Bertrand Russell’s Celestial Teapot.
The following extract is taken from Susser M. The logic of Sir Karl Popper and the practice of epidemiology. Am J Epidemiol 1986;124:711-718, 1986.
He [Karl Popper] would allow that if a hypothesis fails successive tests, it is falsified. For him, however, every affirmative result in the same direction indicates no more than survival of the hypothesis. These tests merely expand the range of outcomes that the hypothesis disallows. They do not affirm or verify, nor do they alter the probability that a theory is true.
In the case of a persisting null result, one can agree and Popper would accept that consistency demands rejection of a hypothesis. Indeed, the inductivists Francis Bacon and John Stuart Mill both argue that the elimination of alternative hypotheses by negative instances contributes more to inference than does the piling up of positive instances. Yet, to “prove” a negative is difficult because alternative qualifying hypotheses are so readily to hand; these render the criterion somewhat less decisive in falsification”
In the first sentence in the paragraph that mentions Karl Popper, I guess I’d like to see the word ‘appropriate’ slipped in before ‘tests’, would that seem reasonable?
And, from the second paragraph we learn that it’s difficult to “prove” a negative. Which we knew already, right, so I’m not sure why Francis Bacon and John Stuart Mill’s opinions on all this might possibly are required.
And their hypothetical opinions, by the way, don’t change these basic facts:
We have no good evidence that MMR does not cause autism (although I accept you allude to some and now no doubt will provide it).
And while I agree it’s very hard to ‘prove’ a negative, my impression is, to be honest, that some politicians and scientists, if they were sufficiently motivated, could have tried a lot harder to assure us of MMR’s safety in respect of autism.
“Given ten years of failures to affirm the Autism-MMR vaccine hypothesis, and plenty of consistency of null results, it seems reasonable to reject the hypothesis.”
And given 10 years of inadequate science and countless accounts of parents who claim to have witnessed their child regress into an autistic state shortly after receiving the MMR vaccine, it seems reasonable that our scientists and politicians should give this matter the attention it deserves, rather than merely insisting that MMR does not cause autism, and in some instances painting concerned parties as ‘stupid’ or ‘hysterical’ or ‘scientifically illiterate’ or as people just ‘looking for someone or something to blame.’
Dear John,
Oh dear. That’s just the sort of response I was expecting.
I think further meaningful discussion is unlikely.
Regards
Anthony
Let’s please get to they crux of this:
1. You, more than once, have alluded to ‘evidence’ that appears to vindicate MMR with regard to any potential to cause autism.
2. I have, more than once, asked you to provide that ‘evidence’.
3. It turns out you are unwilling or unable to provide this ‘evidence’
I asked to see your hand, and it appears it wasn’t such a strong one after all (or perhaps you have no cards at all, we don’t know).
And now you appear ‘cry off’ from the debate, just when it’s getting really interesting and ‘meaningful’.
And then you wonder why individuals express doubt about the safety of MMR in relation to autism. Just for the record, it has at least something to do with people like you – who give the distinct impression that MMR does not cause autism, but don’t care to or simply can’t provide the evidence that shows this to be so).
I can’t wait to see you discuss our exchanges here on your own blog, where I trust you’ll permit me the right of reply.
John,
Are you saying that you don’t even know where to look to find the studies?
I have the papers on this computer, but I am surprised that you are so sure it is shoddy science when you don’t even know which studies you are talking about. You could start by searching my blog for some of the studies, although not all of them are there.
I’m not crying off debate, I’m waiting for you to put forward evidence for your claims. which we now know to be based on nothing more than supposition, rather than knowledge of the studies concerned.
By the way the word evidence does not have scare quotes round it. Do they signify some sort of prejudice at all?
Anthony
“Are you saying that you don’t even know where to look to find the studies?
I have the papers on this computer, but I am surprised that you are so sure it is shoddy science when you don’t even know which studies you are talking about. You could start by searching my blog for some of the studies, although not all of them are there.”
Are you going to answer the questions about the appropriateness of epidemiological evidence in determining cause and effect? Will you accept that it is epidemiological evidence that, in the main, has been used to claim that MMR does not cause autism? And do you accept that from a scientific standpoint, I’m entitled to use the word ‘shoddy’ (as in inadequate) in reference to this research?
I know where to look for the evidence that is claimed vindicate MMR with regard to autism (or at least I think I do). The thing is, Anthony, it’s you who is putting up these studies, so it’s your job to provide them. I mean, does it really seem reasonable for you to ask me to find the studies you say support your stance? You suggest I search your blog, but might not actually find the studies you’re alluding to there anyway? Do you see how faintly ridiculous this seems?
Why not just push a few buttons and provide them here?
As I said, you have a golden opportunity now to show me just how ill-informed I am, by wheeling out all this non-epidemiological evidence you allude to. But yet again you have resisted doing this. Why?
“I’m not crying off debate, I’m waiting for you to put forward evidence for your claims. which we now know to be based on nothing more than supposition, rather than knowledge of the studies concerned.”
Please see my comments on epidemiological evidence above and answer the questions I pose. Please. And so what if my opinion is based merely on supposition (which I maintain it is not)? Why not just wade right in (as I’ve invited you to do several times now)? Because that surely would be the way, would it not, to prove that my stance is merely based on supposition. And that surely would be the most expedient way to show us all that MMR does not cause autism, as you appear to claim. So go for it.
“By the way the word evidence does not have scare quotes round it. Do they signify some sort of prejudice at all?”
They’re not scare quotes, they’re used here as quotation marks. You used the word, and I’m quoting you. The reason that I’m quoting you is because while you’ve used this word, as yet there isn’t any evidence here that the ‘evidence’ exists.
So your claim the science is shoddy is based merely on your observation that epidemiological studies do not prove cause and effect?
Devastating stuff.
Your opinion is based on supposition and credulity in the face of emotive anecdotes.
If it isn’t lay out your detailed critiques of the studies you say do not prove the safety of MMR vaccine.
The burden of proof lies in your court.