I am meta analyzing everything related to listening (e.g., listening and leadership, listening and job satisfaction, etc.). I would like to have all the effects in a single file and run separate meta analyses based on topic. [I have some 70 topics].

I am a newcomer to R, and thought that the tapply function could work, but could not figure out how to use it.

To test the idea I tried to create a command that will run a separate meta-analysis for the variable r"moderator". First, I successfully ran metacor with the variable as a moderator:

```
metacor(rho,N,Study,data=Leadership,comb.fixed=F,prediction=T,byvar=Leadership$Moderator)

```

Then, I tested successfully the logic of tapply:

```
tapply(Leadership$rho,Leadership$Moderator,mean)

```

Now, I wanted to replace the mean function with metacor and tried unsuccessfully to write

```
tapply(,Leadership$Moderator,metacor(rho,N,Study,data=Leadership,comb.fixed=F,prediction=T))

```

I would greatly appreciate any advice.

Avi