Hi B. Bilal,

following the Higgins description, you should interpreted it as 0% (ie, truncate it to 0).

"Negative values of I2 are put equal to zero so that I2 lies between 0% and 100%. A value of 0% indicates no observed heterogeneity, and larger values show increasing heterogeneity."

Measuring inconsistency in meta-analyses, BMJ 2003, Higgins, Thompson, Deeks, Altman

There is a description of a multivariate or other variations of I2 (from White) to avoid negative I2 (Statist. Med. 2012, 31 3805–3820)

Hope it helped,

Cheers

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC192859/

http://onlinelibrary.wiley.com/doi/10.1002/sim.5453/pdf

thanks a lot Otavio T Ranzani ·