The I² statistic describes the percentage of variation across studies that is due to heterogeneity rather than chance (Higgins and Thompson, 2002; Higgins et al., 2003). I² = 100% x (Q-df)/Q. I² is an intuitive and simple expression of the inconsistency of studies’ results. Unlike Q it does not inherently depend upon the number of studies considered. A confidence interval for I² is constructed using either i) the iterative non-central chi-squared distribution method of Hedges and Piggott (2001); or ii) the test-based method of Higgins and Thompson (2002). The non-central chi-square method is currently the method of choice (Higgins, personal communication, 2006) – it is computed if the 'exact' optionis selected. http://cccrg.cochrane.org/sites/cccrg.cochrane.org/files/public/uploads/heterogeneity_subgroup_analyses_revising_december_1st_2016.pdf

It appears that the analysis can be conducted using Review Manager.

Assessment of heterogeneity is the default analysis option for the Rev Man, and it is a free software. You may put your data into it, which can help to present the results you want.

You may refer to the analysis approach of this paper:

Article Prevalence of depression among nursing students: A systemati...

Dear Mohammad

Do you ask for an interpretation of the heterogenity in your analysis?

In your analysis, some of the heterogenity is caused by the study by Dash et al. and Nadir et al. who reported some of the most outstanding results and an explanation could be that they applied the treatment over 7 days, wereas it was applied for fewer days in the other studies (I might have misinterpretated your table). If you subgrouped the studies with Dash and Nadir in one group and the remaining studies in the other group, I guess the statistical heterogenity would be lowered drastically, as more confidence intervals would overlap eachother.

I do not know whether this is a plasible explanation. There are relatively few studies and what we see could be due to other factors, such as impact from bias.

Best regards

Martin

Thank you

I² statistics will help you determine that.

My question about proportion meta analysis