For my final thesis I performed a meta-analysis with different subsets (subgroup analysis). Although I systematically searched the literature (I was brutally sophisticated), depending which subset I analyze, the Egger's Test is significant or not, indicating publicaton bias or not.
However, on the undifferentiated subset although the Egger's Test is significant, the Trim and Fill method does not add any studies to the sample.
Trim and Fill method is based on:
Duval, S., & Tweedie, R. 2000a. A Nonparametric “ Trim and Fill ” Method of Accounting for Publication Bias in Meta-Analysis. Journal of the American Statistical Association, 95(449): 89–98.
Duval, S., & Tweedie, R. 2000b. Trim and Fill: A Simple Funnel-Plot-Based Method. Biometrics, 56(June): 455–463.
I have several questions:
1) How to interpret that depending on the subset analyzed, the Egger's test is significant or not (I cannot derive a pattern or something similar).
2) Why does Trim and Fill not add studies, although Egger's Test is significant?
3) Would you add any additional tests?
I will now add some pictures of the results, so you can better follow my thoughts. Thanks for any help.