. 2017 Mar 14;356:j667. doi: 10.1136/bmj.j667
Published by the BMJ Publishing Group Limited. For permission
to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions
This is an Open Access article distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/.
Fig 2 DerSimonian and Laird random effects summary estimate