How old do you think Martin Luther King Jr. was when he was assassinated?

That question has been used to help gauge how good people are at making predictions and to help them get better.

I’m going to try to build on it here to make a point about the need to look rigorously at past forecasts and decisions to calibrate how good we are (or, often, aren’t), so we can continually improve.

The question about MLK is deliberately unfair. How can we be expected to know his exact age?

So, pick an age, then give yourself a range, expanding in both directions until you figure you have a 90% chance of having his actual age fall within that range. (Go ahead and write it down. I’ll wait.)