Cohen's d does not correct for multiple comparisons
I am performing a mixed 2x2 ANOVA and when I explore the effect sizes of the post-hoc test t, there is a note: "Cohen's d does not correct for multiple comparisons". See attached file of post hoc comparisons, I am interested in Post-pre comparisons of both groups.
I was wondering if It would be correct to perform a dependent t test with the data of each group in order to obtain the effect size corrected. See attached file of paired samples t-test.
Thanks in advance.

Comments
I have been thinking about it and I would like to express one possible idea, it would be great if someone could help me.
I have noticed that JASP compute Cohen's d by the formula d = t/sqrt(n), isn't it?
Then, if the post-hoc test reports the t value and I know the n, it would be correct to calculate the Cohen'sd using the above formula?
I accept any suggestion.
Thanks in advance.
Hi Vicente,
I'm not an expert on frequentist methods for multiplicity correction. Have you Googled this? It does seem reasonable -- a little ad-hoc, but then again, it is a frequentist procedure :-) and there may be a rationale.
Cheers,
E.J.
Hello,
I have the same question and I didn't find any useful information by googling.
Thanks in advance
Matthew