CODEWITHSUNDEEP
r
user3346690
user3346690

Reputation: 1

Meta analysis from mean-effectsizes for overlapping samples

I run a meta analysis and use the metafor library to calculate fisher z transformed values from correlations.

>meta1 <- escalc(ri=TESTR, ni=N, measure="ZCOR", data=subdata2)

As some of the studies I include in my meta-analysis, overlap in samples (i.e. in Study XY, 5 effect-sizes are reported from the same N), I need to calculate means of the standardized z-values. To indicate overlapping samples, I gave all effect sizes IDs (in Excel) which are equal if the samples overlap.

To run the final metaanalysis, I would like R to sum the standardized effect sizes from IDs and calculate means for the final metaanalysis.

So the idea is:

IF Effect_SIZE_ID (a variable) is similar in two lines of my df, then sum both effect sizes and divide it by two (calculate the mean). Provide this result in a new column.

As I am a full newbie, please let me know if you require further specification! Thank you so much in advance.

LEon

Upvotes: 0

Views: 342

Answers (1)

iraserd
iraserd

Reputation: 689

Have a look at the summaryBy command in the doBy package.

mymean <- summaryBy(SD_effect ~ ID, FUN = mean, data = data)

Should work in general (if you provide some sample data it is easy to check if that does what you need).

Upvotes: 1

Related Questions