Check heterogeneity, quality, and publication bias. And if the results are acceptable, you can conduct meta-analysis for 19 studies. Meta-analyses often aim for at least 10-20 studies to ensure a sufficient sample size for meaningful statistical analysis and to provide a comprehensive synthesis of the evidence.

You can include non-English references, such as Farsi papers but consider your

Cabilability to understand and interpret the results of these studies. If language barriers prevent thorough evaluation or synthesis of these studies, you should ignore them.

Dear Heba,

Your answer was the best. Now, I know what to do.

Thank you.

Maryam

You can conduct a meta-analysis of 2 studies, so 19 is plently.

If you are confident you can accurately translate and understand the Farsi papers, they may be included, otherwise leave them out.

Note: publication bias and heterogeneity is typically assessed as part of a meta-analysis (not before). You can assess the risk of bias before, and may decide to exclude some studies from the meta-analysis on that basis, but they would still be included in your review.

Dear Joseph,

Actually, after reading the 19 studies in more detail, 5 had to be left. But I think you are right. Now, I am working on the review section and then I will work on publication bias and heterogeneity.

Thank you for your reply

14 is plently