The MMR Vaccine Controversy
The controversy over whether and how often to vaccinate children remains a volatile one. But how much does this debate match the empirical data and objective reasoning? The Rootclaim analysis of the MMR vaccine and its alleged ties to autism illustrates the challenges of objective, rational decision-making.
Analyze Objectively and Unemotionally
Far too many people are unable to analyze this topic without letting emotion get the better of them. To avoid that trap, use hard data. Evaluate the source of the information. And instead of tear-jerking pictures and stories, find reliable statistics. Rootclaim’s crowdsourced platform incorporates evidence supporting all of the hypotheses. It then evaluates each piece of evidence on its own merit.
Understand the Numbers
Looking at data is necessary, but understanding those numbers is also important. It is easy to manipulate numbers or misinterpret figures. For example, in the MMR vaccine analysis, we detail the rise in autism diagnoses. In 1966 approximately 4 in 10,000 people were diagnosed with autism. But by 2016, that figure was up to 1 in 68. So did autism really become that much more prevalent? The more probable explanations include improved screening techniques and broader diagnostic criteria. Jumping to conclusions without properly understanding the relationship with the data is as foolhardy as ignoring information.
Calculate the Priors
The first step in an analysis is the evaluation of the prior likelihoods of each hypothesis being true. Prior likelihoods are the estimated likelihood of an event occurring without considering any evidence specific to this case. For example, in the MMR analysis, even before looking at the evidence, we know that a conspiracy is highly unlikely. An international conspiracy could explain certain pieces of evidence well. However, it is nearly impossible to coordinate all relevant parties and prevent the truth from getting out. There is no record of a conspiracy of this scale and duration, even considering comparable industries. Therefore, in the prior evaluation, a conspiracy explanation is estimated as highly unlikely. In contrast, it is considered extremely likely that there is no causational link with autism. This is because FDA approved drugs rarely show any evidence of autism as a side effect.
Evaluate the Evidence
Another key element is gathering and evaluating your evidence objectively. Rootclaim does this through crowd-based collaboration and by listing each piece of evidence separately. Remember that not every bit of evidence is of equal reliability or strength. Instead, try to find the weak points, alternative explanations, and their respective likelihoods. In the MMR vaccine case, the now infamous Wakefield study provides a good case study. Although Wakefield claimed to find a link between vaccines and autism, his flawed research methodology tainted his findings. Ultimately his peers discredited his research.
Correlation vs. Causation
Watch out for false assumptions of causality and other distorted relationships. Not every correlation implies causation. Instead, look for the most likely explanation(s). For example, the MMR vaccine case includes a study on Japanese children. In the study, as MMR vaccination rates in Japan dropped significantly, autism rates rose. Should we conclude therefore that vaccines prevent autism? Without more evidence, that conclusion isn’t any more credible than assuming that vaccines do cause autism. Instead, we need to consider all of the likely alternative explanations, and weigh the likelihood of each one separately.
More is Better
Increasing the evidence examined strengthens the conclusions. Statistically, the more times a study is independently replicated, the more reliable the results. In other areas as well, the broader and larger the pool of data, the more reliable the statistical inference. In the MMR vaccine case, we only found one (flawed and retracted) study pointing towards a vaccine-autism correlation. On the other hand, many follow-up studies have failed to find such a relationship. Even ignoring the flaws of Wakefield’s study, his findings are extremely unlikely to be right, given so much conflicting research.
Put Life into Perspective
Putting things in perspective is important. But it’s also a great challenge for people. Is it possible that MMR vaccines cause autism? Sure it’s possible–by virtue of it not being impossible. But given all of the relevant data, a vaccine-autism link is extremely farfetched. A CDC report called such a link “very rare.” In CDC lingo, that means between a 1 in 100,000 to 1 in 1,000,000 probability. Our own analysis finds a 99.9% likelihood of the vaccine not causing autism. That means that it is 999 in 1000 likely that no such link even exists–a very strong vote of confidence (and even in that 1 in 1000 likelihood that there is a link, the causational relationship could still be very remote, with a low likelihood of actually developing autism as a result of vaccination).
On the other hand, avoiding vaccines puts one at risk of contracting diseases. Thus only evaluating the evidence and data objectively, and correctly assessing correlations, lead to the most reliable conclusion. Use the Rootclaim method to avoid being fooled by emotional arguments, manipulated data or misinterpreted information.