Institutions in health care, education and other public services are under constantpressure to perform to high standards and with efficiency. Assessment of theirperformance is often problematic because it either ignoresimportant backgroundvariables of their patients, students or clients (the case-mix), or adjusts for themin a way that is not equitable or transparent. We apply a methodof indirectstandardisationmotivated by the potential outcomes framework, in which weconsider the hypothetical scenario of an institution’s caseload being dispersed fortreatment throughout the domain of assessment (the country’s institutions). Thetarget of estimation is the difference of the means of the outcomes in the realisedand hypothetical settings. The method is applied to estimating the prevalenceof bronchopulmonary dysplasia (BPD) in extremely preterm-born infants in theneonatal units and their networks in Great Britain in 2017. The prevalence ofBPD is an audit measure in the UK National Neonatal Audit Programme.