Dear fellow researchers, I am currently conducting a meta-analysis for my master's thesis in psychology. For that matter, I stumbled upon your metafor package which has been very helpful for me! However, I have some trouble implementing the right R code for my analysis. I am running a meta-analysis on the relationship between self-efficacy and scholastic achievement (using correlation coefficients). It will be analyzed using multilevel analysis using a random-effects model because I have several articles with multiple effect sizes which I want to include individually controlling for their dependency. Therefore, I have (dependant) effect sizes that are nested within (independent) samples. Each independent sample is coding with an unique number in the variable "sample_nr" and each dependant effect size for a certain sample is coded with an unique number in "effect_nr". So, a sample with multiple effect sizes would be coded with an identical "sample_nr" and different "effect_nr" for each effect size. My R code is as follows: rma.mv(yi, vi, random = ~ 1 | sample_nr/effect_nr, data = se_ach) Is this the right code for my purpose? Thank you for your advice. Best regards, Denise Braul
[R-meta] multilevel meta-analysis using metafor
2 messages · brauldeq, Viechtbauer Wolfgang (STAT)
Yes, that would be appropriate/sufficient, assuming there is no overlap in the subjects used to compute the various correlation coefficients within the same study. But I suspect that may not be the case. If so, the covariances of the correlations are not 0 (as is assumed by the model below). Best, Wolfgang
On 08/30/2017 11:54 AM, brauldeq wrote:
Dear fellow researchers, I am currently conducting a meta-analysis for my master's thesis in psychology. For that matter, I stumbled upon your metafor package which has been very helpful for me! However, I have some trouble implementing the right R code for my analysis. I am running a meta-analysis on the relationship between self-efficacy and scholastic achievement (using correlation coefficients). It will be analyzed using multilevel analysis using a random-effects model because I have several articles with multiple effect sizes which I want to include individually controlling for their dependency. Therefore, I have (dependant) effect sizes that are nested within (independent) samples. Each independent sample is coding with an unique number in the variable "sample_nr" and each dependant effect size for a certain sample is coded with an unique number in "effect_nr". So, a sample with multiple effect sizes would be coded with an identical "sample_nr" and different "effect_nr" for each effect size. My R code is as follows: rma.mv(yi, vi, random = ~ 1 | sample_nr/effect_nr, data = se_ach) Is this the right code for my purpose? Thank you for your advice. Best regards, Denise Braul