Comments on Divergence vs. Decision P‐values: A Distinction Worth Making in Theory and Keeping in Practice – or, How Divergence P‐values Measure Evidence Even When Decision P‐values Do Not by Greenland in Scandinavian Journal of Statistics, 2023

Abstract

Greenland (2023) distinguishes between P‐values used for data description and P‐values used for declaring significance. That's a useful distinction and Greenland has advanced our field by making it. That distinction comes with the idea that describing data with statistical models is often a useful task for statisticians. Again, we agree. Along the way, Greenland also says (i) there is such a thing as a “measure …of evidence [from data] against a statistical hypothesis or model” without regard to alternatives; (ii) “a discrepancy P‐value is an ordinal description …”; (iii) descriptive “P‐values can be derived to provide coherent measures of refutational evidence”; and a few other things that deserve comment and discussion.