## Solved – Tau, Tau squared and I squared =0

I've used the confint() function of R package metafor to calculate heterogeneity in random effects models in a meta-analysis. I get sensible values for the various parameters (tau, tau^2, I^2) for most of the calculations I have run, however am getting back 0 values for all three parameters for one particular analysis. I have checked … Read more

## Solved – Q-Test of Heterogeneity for only two effect sizes

I am using the Q-Test of Heterogeneity to investigate if several effect sizes derived from two different studies are significantly different from each other. More precisely, I have, for every effect of interest, a Cohen's d from one study, and one from the other, and their respective variances. I calculate the Q-value (using the formula … Read more

## Solved – Panel regression with multiple fixed effects and heterogeneity

For a research project I am supposed to estimate a panel regression model on a dataset with user data over observation time (the sample is assumed to represent general population). The supervisor is adamant about estimating a linear regression with fixed effects on variables such as gender, education level, month of year and so on. … Read more

## Solved – Calculating heterogeneity (Cochrane \$Q\$ and \$I^2\$ statistics) in random effects model

I want to ask whether I can calculate the Cochrane \$Q\$ and \$I^2\$ statistics in a random effect model. I collected some data from different areas and want to compare the prevalence of allergic sensitization on different areas. However, the Cochrane \$Q\$ and \$I^2\$ statistics were quite large (usually, >= 90 for \$I^2\$) and I … Read more

## Solved – How to calculate confidence intervals for I-squared in order to assess heterogeneity between two pooled studies

I am conducting a meta analysis and for some of my pooled data, there are only two studies available. Based on this publication I have been calculating confidence intervals around I-squared in order to assess heterogeneity. I've used the equation provided in chapter 16 of Introduction to Meta-analysis (Borenstein, Hedges, & Higgins, 2011) page 124 … Read more

## Solved – Computation of Network Homophily / Heterogeneity

I am quite confused about the calculation of network homophily in network analysis. Right now I am computing the homophily using the following function, which has been written and also described by the following URL: http://dappls.umasscreate.net/networks/calculating-network-homophily-part-1/. Well the definition of homophily in social science is "the tendency of individuals to associate and bond with similar … Read more

## Solved – Heterogeneity statistics with fixed effects model in RevMan

Since a fixed-effects meta-analysis assumes that the studies are all estimating the same underlying effect, when the Cochrane RevMan software reports a Q and \$I^2\$ statistic with a fixed-effects analysis what exactly are they reporting? The manual says: Note that a random-effects model does not ‘take account’ of the heterogeneity, in the sense that it … Read more

## Solved – Multiple Time Fixed Effects in Panel Regression

I have weekly panel data for more than a hundred cities. The independent variables are temperature and precipitation. The time dimensions; year, month, and week – likely have time invariant characteristics and are all important for proper estimation. I was wondering if there are any issues in controlling for all three fixed effects (year, month, … Read more

## Solved – Correct interpretation of Tau and Tau^2 in meta-analysis of different measures

Simple question. Given that Tau is defined as the estimated standard deviation of underlying true effects across studies (and, accordingly, Tau^2 as the variance), how can I interpret this data in different meta-analysis (i.e., meta-analysis of odds ratio and meta-analysis of mean differences)? E.g.: if I perform a meta-analysis of mean differences, obtaining a pooled … Read more