International journal for equity in health
Moving beyond the average: a method to measure health related-inequalities within randomised trials
By Abel ZDV, Cole S, Erreygers G and 2 others.
Abstract
Background
Randomised trials seldom investigate the impacts interventions have on socioeconomic inequality in health, focusing instead on their average treatment effects.
Methods
We illustrate how standard measures of inequality such as the corrected concentration index can be reported in randomised experiments to quantify the interventions' socio-economic distribution effect alongside more traditional average treatment effects. We illustrate this with a proof-of-concept example using a study on the impact of information and financial incentives on verified COVID-19 vaccination uptake in rural Ghana (n = 2,271). We estimate the distributional treatment effects of informational public health messaging, low- and high-cash financial incentives relative to a placebo group and present this information on an achievement plane.