Kernel density plots of propensity score distributions in the included and excluded populations. Kernel density plots of propensity score distributions in the included and excluded populations. Plots represent the estimated density of predicted probabilities of exclusion in the included and excluded groups. Regions of overlap identify populations with similar probabilities of exclusion. ACEi, ACE inhibitor; ARB, angiotensin receptor blocker; PCI, percutaneous coronary intervention; LVSD, left ventricular systolic dysfunction. Jeffrey Bruckel et al. BMJ Qual Saf 2017;26:189-199 Copyright © BMJ Publishing Group Ltd and the Health Foundation. All rights reserved.