According to this, a funnel plot should only be used when there are more than 10 studies. Sterne, J. A., Sutton, A. J., Ioannidis, J. P., Terrin, N., Jones, D. R., Lau, J., ... & Tetzlaff, J. (2011). Recommendations for examining and interpreting funnel plot asymmetry in meta-analyses of randomised controlled trials. Bmj, 343, d4002.

Hi Crasta! Yes, you are right about 10 studies are more. Some suggest that you change the P value to .1 and above instead of the traditional .05. How scientific is this approach? There are competing view and approaches among researchers and reviewers. Thanks.