Equity Effects of Disease Prevention Control Coverage on Avoidable Care Delays in Kenya: A Target-Trial Emulation

Target-trial emulation offers a disciplined way to define intervention contrasts from observational health data, but the protocol that is usually written down still targets a population-average effect. That default is a poor match for Kenyan disease-prevention and control programmes, which are publicly judged by coverage while avoidable delays in reaching effective care remain patterned by wealth, county, insurance status and gender. This methodological article specifies, and does not execute, an equity-explicit target trial whose causal question is whether alternative coverage regimes compress or widen delay disparities rather than whether they shorten mean delay. The argument reconstructs eligibility, time zero, treatment strategies, follow-up and outcomes so that equity enters the estimand, drawing on the three-delays tradition, effective-coverage measurement and the inverse-equity hypothesis as a mechanism to be tested rather than a conclusion. Identification is argued to fail in characteristic ways inside devolved Kenyan systems: positivity thins inside poorly resourced counties, interference travels through community health structures, and restriction to those who present for care opens a collider between need and access. An emulation architecture is outlined against national information systems that could, in principle, support the protocol. The contribution is a trial specification and a map of threats, not a numerical effect.