USING BASEBALL ANALOGIES TO PROVIDE A YARDSTICK FOR COMPARING PROBABILITIES. I argued here that people are by now accustomed to using probabilities rather than words in understanding weather forecasts. When I was growing up, weather forecasts avoided numbers and only used words (for example,”partially cloudy”). Now people are accustomed to forecasts which are expressed as “a 10% chance of rain”. I argued here that rating agency forecasts should be expressed and reported as probabilities.
Nate Silver in this article at the fivethirtyeight website analyzing a wide range of probabilities for the 2014 elections for the US Senate gives a useful yardstick for comparing probabilities. He points out that you can think of a 40% probability of the Democrats holding the Senate as the likelihood that Ted Williams would get a hit in an at bat in 1941 (when Williams’ .406 batting average made him the last man to hit over .400). A 34 % chance is the equivalent of Tony Gwynn getting a base hit in an at bat in 1989. To give some more of the flavor of Silver’s analogy, he says that if the Democrats don’t carry Georgia, “Democratic chances of keeping the Senate would be down to about 25 percent. Twenty-five percent chances come in fairly often, too — they come in 25 percent of the time! — but Democrats would be downgraded from Gwynn to Alfredo Griffin.”