I've calculated an effect size for the difference between two standardized pre-post differences of two independent groups of subjects.
That is: $[Mean_{dif_{group~1}}/SD_{dif_{group~1}}]-[Mean_{dif_{group~2}}/SD_{dif_{group~2}}]$
where $Mean_{dif}$ is the difference between the means of pre- and post-tests of each group. And $SD_{dif}$ is the standard deviation of the difference scores for each of the two independent groups.
I was wondering what is the standard error of this effect size?
P.S1: This effect size also appears in Table 1 (row 5), p. 114 of this article. The same article, however, doesn't seem to provide the sampling variance of this effect size in Table 2, on p. 117.
P.S2: This answer provides an SEM solution to obtain SE for pre-post differences in only one group of subjects.