Basis of meta analysis and whether we should take an average of data, if experiment was conducted in different years or each year results reflect a separate observation
First of all please see is a study for your variables and thier bivariate relation is present.In case it is you could take from the papers any three values.SD and Means for cohen's D value,Odds ratio for effect size of other family and r that is Pearsons correlation for "R" family effect size.
You may use Open Meta. It is great for those who are doing a meta-analysis for the first time. Otherwise, you may use other statistical Softwares like Stata or R too.