Search Archives

Dear All, This may be too basic to ask. But can the r value chosen to represent the common correlation among effect sizes within studies be a negative one? For example, is there a situation where I would need to...

Dear Wolfgang and list members, Is there any function or code for rma.mv models that would work like lme4::isSingular()? I ask this because, given a fixed number of moderators, I sometimes want to empirically explore how much room...

Dear Colleagues, I have recently learned about the RVE estimation and the usefulness of the clubSandwich package in this regard. I read the documentation of the package, but I was unable to determine which function or functions in the package...

Dear Meta-Analysis Experts, My sample of longitudinal studies both provide the raw descriptive statistics (mean, sd) for groups at different time points as well as the unstandardized regression coefficients for group*time interactions often adjusted for various confounding variables...

Dear Dr. Pustejovsky (and other Meta Experts), I've run into a potential bug in clubSandwich::Wald_test(). The error says: Error: the leading minor of order 6 is not positive definite Would you please confirm whether the error in...

Dear Wolfgang, In the latest version of metafor, I realized there are a couple of new functions specifically made for correlations (that's awesome!). I understand the use of rclac() which provides the V for rma.mv(). But I'm...

Hello Wolfgang, I want to exponentiate the fixed part of my model below, is there a way to preserve the appearance of the output as in `coef(summary(res))` but just display all the columns in their exponentiated form? I...

Dear Dr. Pustejovsky (and other Meta Experts), I've run into a potential bug in clubSandwich::Wald_test(). Would you please confirm whether the error in the following reproducible example is a bug or not? Any possible fix? Best, Stefanou...

Dear Wolfang and the list Members, I've done a post-hoc after my 3-level model. Below is part of the results. At Baseline, elementary was larger than the mixed group by .251 (ignore pval). At post-test1, elementary...

Dear Experts, I need some guidance for modeling two types of effect sizes (for two different meta-analyses) using the rma.mv() program in metafor. First, I have computed the standardized mean change (SMCC) between each pre-test and the...

Dear Meta Community, We are coding for a continuous, intervention-level moderator that can take whole numbers 1, 2, 5 etc. This moderator has to due with how targeted the intervention has been in addressing the flaws that came up...

Dear List Members, We are meta-analyzing a number of longitudinal studies. But our studies have three general research designs (below). We are wondering, other than creating study-level moderators to distinguish between the designs or how many treatments each...

Dear Meta Community, My studies measure the effect of a training program to improve teachers' self-efficacy. We have coded for the 'length of the training sessions' (training_hr) up until each testing occasion (time). At the pre-testing occasion...

Dear Meta-Analysis Colleagues, We are meta-analyzing 73 longitudinal studies. But we have doubts amongst us regarding how to combine the longitudinal effects of these studies. On the one hand, if we use time only as an indicator of...

Dear Wolfgang and Expert List Members, Why `study` with 57 levels in model `res` gives `sigma^2.1 = 0.0200` but `study` with 57 levels in model `res2` gives `sigma^2.1 = 0.0122`? (SAME LEVELS BUT DIFFERENT RESULTS) Why...

Michael, Given the history behind the "sneaky" nature of singular models and how easily people fall victim to it (https://arxiv.org/pdf/1506.04967.pdf), I would think it may not be advisable to simply fit the models and...

Dear Meta-analysis Experts, I just came across the following post **https://stat.ethz.ch/pipermail/r-sig-meta-analysis/2022-February/003851.html** about the weights in rma.mv() models. I have two questions. 1- It looks like the...

Hello Wolfgang, I'm a second second year master's student in psychology at the University College of London. I don't currently own a social media platform or personal website (I certainly should set up one for myself when...

Thank you so much, Wolfgang. I must admit that I failed at achieving this on my own. In my model below, I want to test: (coef 4 - coef 1) - (coef 5 - coef 2) Would that be possible either in anova...

Resending Model 2: #*********************** MODEL 2: #*********************** rma.mv(yi ~ time_btw + time_wthn, vi, random = list(~ time_wthn | study, ~time_wthn | study), struct = c("GEN","CAR"),data=data) Variance Components: outer factor: study (nlvls = 49) inner term: ~time_wthn (nlvls = 9...