In the last few Uncertainty Wednesdays, we have been looking at various fallacies arising from our lack of appreciation of uncertainty, such as imperfect correlation (narrative fallacy) and the baserate fallacy. Today we will look at hindsight bias, for which the Mueller Report provides as perfect example. Hindsight bias is the tendency after an event occurs to conclude that we knew the event would occur all along. It is an ex-post reduction of the uncertainty that actually existed prior to the event.

Leaving aside the pretty important fact that very few people have actually read the Mueller report, it is clear that at a headline level it did not find sufficient evidence for a criminal charge of collusion. This has led lots of pundits to loudly proclaim how they were right all along and some of them to go further by saying that this proves the investigation wasn’t needed. These statement are of course fueled by political motives but they are also hindsight bias at work.

Consider a different situation for a moment. You are buying a house that you really like. It is from a time period in which asbestos was used a lot and your spouse pushes for an asbestos inspection, but you are reluctant to spend the money. After a contentious debate you go ahead with the asbestos inspection. The inspection finds no asbestos. You: “I told you all along this is a great house and this inspection was a total waste of money.”

This example, because it is not political, makes the hindsight bias fallacy quite obvious. There was real uncertainty about whether there is asbestos or not in the house. When your opinion of “no asbestos” was confirmed in hindsight you take this as evidence that you were definitely right, that there was no uncertainty to begin with and hence the inspection was a waste. I have a feeling that the comments on this post will be full of hindsight bias on the Mueller report, presented even after having read this post.

The arguments will go something like, “Albert, in your example there was real reason to suspect asbestos based on when the house was built, but there was no reason to suspect collusion.” For this, I simply leave you with 

And the meeting at Trump tower. And the pro Russia change in the GOP platform following Trump’s nomination. But please do go ahead, because I will be happy to have the comments confirm the point of the post.