In case of three variables (l, h, and m), overlapping Fisher-z
transformed correlation coefficients can be computed between variables l and h
and variables l and m. The function computes the variance of the difference
between these two overlapping Fisher-z transformed correlations. For a derivation
of this variance see van Aert & Wicherts (2023).
The variance that is computed with this function can be used to correct for
outcome reporting bias by including the variance as a moderator in a
(multivariate) meta-analysis. Please see van Aert & Wicherts (2023) for
more information.