How is health equity considered in policy evaluations employing quasi-experimental methods? A scoping review and content analysis

Abstract

Public health researchers employ quasi-experimental methods (QEM) to evaluate the effects of policies. Whilst some policies are designed to improve (health) equity, others may intentionally or unintentionally have detrimental effects on disadvantaged populations. We thus sought to investigate how health equity is addressed in policy evaluations which employ QEM. We conducted a content analysis on studies sourced from a scoping review. We drew a random sample of 350 records identified in systematic database searches in Medline, EMBASE, and EconLit (December 2022). Studies that employed QEM labels and examined public policies implemented in the WHO European region were included. We extracted data on study design, policies, and populations; assessed whether outcomes were examined in population sub-groups (as defined by PROGRESS-Plus criteria); and analysed discussion sections for equity-related conclusions. We included 59 studies, of which 39 (66.1%) studies considered health equity—albeit to variable depth. Twenty-five studies were focused exclusively on examining policy outcomes in a disadvantaged population (42.4%), of which 19 studies evaluated policies that targeted disadvantaged groups (e.g. minimum wage, social housing policies). Outcomes were stratified for one or more sub-populations in 22 studies (37.3%), most commonly for gender (n = 15, 25.4%) and a measure of socio-economic status (n = 13, 22%), particularly income and employment. Equity-related results and implications were discussed in 24 studies. While policy evaluations employing QEM have considerable value for informing decision-making in public health and other sectors that influence health, their potential to investigate equity impacts is currently not harnessed.