PT - JOURNAL ARTICLE AU - Gary Abel AU - Marc N Elliott TI - Identifying and quantifying variation between healthcare organisations and geographical regions: using mixed-effects models AID - 10.1136/bmjqs-2018-009165 DP - 2019 Dec 01 TA - BMJ Quality & Safety PG - 1032--1038 VI - 28 IP - 12 4099 - http://qualitysafety.bmj.com/content/28/12/1032.short 4100 - http://qualitysafety.bmj.com/content/28/12/1032.full SO - BMJ Qual Saf2019 Dec 01; 28 AB - When the degree of variation between healthcare organisations or geographical regions is quantified, there is often a failure to account for the role of chance, which can lead to an overestimation of the true variation. Mixed-effects models account for the role of chance and estimate the true/underlying variation between organisations or regions. In this paper, we explore how a random intercept model can be applied to rate or proportion indicators and how to interpret the estimated variance parameter.