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.