11 October 2009

Many people have debated the merits of Bayesian statistics versus Frequentist statistics: very recently there was this discussion in Bayesian Analysis by Gelman. It’s a fascinating discussion and I’m just learning to ins and outs of different arguments myself.

First, I want to point people to this (short) but very insightful article by Tony O’Hagan. There are many ways of looking at the difference between Bayesian and Frequentist methods and this article makes one particular (a bit philosophical) viewpoint very clear.

I’m certainly not knowledgeable enough to take a stand in this debate but one thing I do have a strong opinion about: Bayesian methods are much easier to understand! In most statistics 101 classes we are taught a bit of point estimation (e.g. estimating a mean, a variance) which I think is understandable, but then people get into hypothesis testing and suddenly have to reason about following statements: (quoting Wikipedia here): “Assuming that the null hypothesis is true, what is the probability of observing a value for the test statistic that is at least as extreme as the value that was actually observed?”. I certainly find this a really complicated notion to reason about. The Bayesian alternative would say something like: “What is the probability of generating the observed value for this particular model”. It is the same kind of statements as “What is the probability of generating a five from a fair dice”.

I honestly think statistics would be a lot more understandable (and hence I think enjoyable) if we were teaching Bayesian statistics before getting into more advanced frequentist methods. I really wonder whether there are schools out there where the undergrad stats curriculum is based on the Bayesian approach?