I need to calculate inverse variance weights of each study that is included in meta analysis. What do I need to know to obtain inverse variance weight for each study?
you need the standard error (SEi) of the effect coefficient bi for each study . The weight for each study i is wi =1/ SEi2 . The weghted mean effect coefficient is then b = Sigma (wi bi)/ Sigma wi
If you do not know the variance apriori, a simple thing to do will be to assume Poisson distribution. It means that you assume that the variance is proportional to the sample size and variance of the mean is inversely proportional to the sample size ....
you need the standard error (SEi) of the effect coefficient bi for each study . The weight for each study i is wi =1/ SEi2 . The weghted mean effect coefficient is then b = Sigma (wi bi)/ Sigma wi