PT - JOURNAL ARTICLE AU - Kathryn S Taylor AU - Kamal R Mahtani AU - Jeffrey K Aronson TI - Combining and converting groups when extracting data for meta-analysis AID - 10.1136/bmjebm-2020-111647 DP - 2021 Feb 08 TA - BMJ Evidence-Based Medicine PG - bmjebm-2020-111647 4099 - http://ebm.bmj.com/content/early/2021/02/08/bmjebm-2020-111647.short 4100 - http://ebm.bmj.com/content/early/2021/02/08/bmjebm-2020-111647.full