How to Make Accurate Predictions

And why experience doesn’t help much.

As a litigator, I make intuitive predictions all the time. But does the mere fact that I make them often mean that they’re more accurate than those who make them sporadically? Does experience improve accuracy?

Philip Tetlock says no. This may come as a surprise to the legal profession, a field with no shortage of traditions, in which deference is generously afforded to senior counsel.

This is not always a bad thing. But in the exercise of prediction-making, it might be. According to Tetlock, while experience does not increase prediction accuracy, it does lead to increased confidence in the prediction.

So if we can’t expect senior members of the bar to make more accurate predictions of a legal action than a junior member, who or what can we turn to?

Our answer is base rates.

Paul E. Meehl, famed clinical psychologist, devoted his career to understanding why statistical predictions (base rates) continuously outperformed clinical predictions (expert judgment). Eventually, he established two theories: