Emulation overview — Target trial emulation

Causal question

State the causal question as a comparison of feasible strategies in an eligible population.

Specify target trial

Specify the hypothetical trial protocol, causal estimand, identifying assumptions and analysis plan.

Map to available data

Map every protocol element to available records and disclose proxies, omissions and deviations.

Align eligibility assignment and time zero

Align eligibility, assignment and start of follow-up; do not use future survival or adherence to qualify entry.

Follow strategies

Define strategy adherence, treatment changes, observation end and competing events.

Estimate contrast

Use an estimator appropriate to the contrast, confounding structure and observation process, with compatible uncertainty.

Test assumptions

Assess data support, measurement error, residual confounding and sensitivity to design choices; diagnostics cannot prove identification.

Report

Report both the target trial and its actual emulation, estimates, precision and limitations using applicable TARGET items.

Emulation overview

End flow

Protocol and decision register

Record the protocol, approvals and registration where applicable. Preserve planned decisions and amendments separately from results.

Protocol and rationale evidence

Attach the rationale and dated protocol, retaining amendments. A study registry records study details; a disease registry contains health data. The HMA–EMA Catalogue of RWD studies is one option for relevant studies. Check eligibility and applicable requirements, and record an identifier and timing if registered. Registration does not imply randomization.