In statistics, Cohen's h, popularized by Jacob Cohen, is a measure of distance between two proportions or probabilities.
A "statistically significant" difference between two proportions is understood to mean that, given the data, it is likely that there is a difference in the population proportions.
, h is defined as the difference between their arcsine transformations.
Often, researchers mean "nondirectional h", which is just the absolute value of the directional h: In R, Cohen's h can be calculated using the ES.h function in the pwr package[6] or the cohenH function in the rcompanion package.
[7] Cohen[1] provides the following descriptive interpretations of h as a rule of thumb: Cohen cautions that: As before, the reader is counseled to avoid the use of these conventions, if he can, in favor of exact values provided by theory or experience in the specific area in which he is working.Nevertheless, many researchers do use these conventions as given.