I learned a useful new phrase today: numerator-only data. This is data without anything to compare it to, no denominator. I ran across the term in Frederick Mosteller’s autobiography. He illustrates the problem with the following old joke.
“Why do the white horses eat more than the black horses?”
“Don’t know. Why?”
“Because we have ten times as many white horses as black horses.”
Numerator-only data is data that leaves you asking “compared to what?” If I tell you the NASDAQ stock index closed at 2368 today, is that good or bad? The number by itself means nothing. Is that up or down compared to last week? Last year? If I tell you, for example, that the record high value was 5047, that gives you a denominator to compare it to.