I have brought this post forward as I have just seen a number of people react to this OFSTED report by making some of the errors described here.
As I said last time, people often think probability can be left out of evidence-based decision making entirely. The most common version of this is when we dismiss people’s descriptions of their experiences as unrepresentative or (perversely) anecdotal. Probability is at the heart of how we reason from evidence (particularly limited evidence) to more general observations. If we see something happen, then (unless we are mistaken) it is impossible that it actually never happens, it is less probable that it is rare, and it is more probable that it is common. The more often we see that something happen, and the more people we know who also see it happen, then the more unlikely it is to be rare and the more…
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The Echo Chamber 