Background: In three studies, we have one independent dichotomous IV, two continuous mediators, and a continuous DV. Our a priori hypothesis is that there’s an indirect effect of the IV on the DV through mediator 1 and mediator 2 sequentially (not simultaneously). The IV is identical in all studies, as are the mediators. Although the DV represents the same construct in each study, we assessed it using different items in each study.
I had planned to conduct an internal meta-analysis (in either Comprehensive Meta-Analysis or R) using my bootstrapped regression coefficients and their standard errors for each indirect effect (from Hayes’ PROCESS macro), but then came across this post, which states that the approach requires the exact same DVs. It's unclear to me whether that means conceptually identical or if every item must be exactly the same.
Question: Is it ok to conduct an internal meta-analysis such as this when a) the indirect effect is based on a sequential mediation (not a simple one mediator case) and b) the DVs are the same conceptually but contain different items? C) If not, what are my options?