I²

Measures how much of the difference between studies is real (not chance): 0% = none; high = a lot.

Source: Cochrane Handbook for Systematic Reviews of Interventions (6.5)
Higgins JPT, Thomas J, Chandler J, Cumpston M, Li T, Page MJ, Welch VA (editores)
https://www.cochrane.org/authors/handbooks-and-manuals/handbook/current
Where, in the source: ch. 10, §10.10.2 — Identifying and measuring heterogeneity
Checked at the source on: 2026-08-10
Verbatim: The official passage from this source is transcribed and checked in our own method document, with the date of verification.
Who wrote this: The wording of this entry is ours, written for people outside the field. The concept and its limits come from the source above, against which this wording is checked — it is neither a translation nor a copy of it.