[From Bill Powers (2008.12.10.0658 MST)]

I was looking up the meaning of “effect size” and found the

following table, which shows the relationships between CHohen’s d (effect

size expressed as difference between means divided by standard deviation)

and r (Pearson’s r, correlation).

Note that a correlation of 0.371 goes with an effect size that is called

“large”, and one of 0.243 goes with “medium.” This is

rather sad. If I were working in a field where those definitions applied,

I would be terribly discouraged.

Best,

Bill P.