Evidence-appraisal glossary
Target Trial Emulation
A framework for analyzing observational data by first writing down the randomized trial you would ideally run, then emulating each of its features (eligibility, treatment start, follow-up, outcome) as closely as the data allow. It disciplines the analysis against common time-related biases.
Also called: emulated trial, hypothetical target trial.
Target trial emulation forces analysts to specify the full protocol of a hypothetical trial before touching the data. Aligning the moment of eligibility, treatment assignment, and start of follow-up, often called time zero, prevents mistakes such as immortal time bias that arise when these are defined inconsistently. It cannot manufacture randomization, so unmeasured confounding remains a real concern, but it makes observational analyses more transparent and more directly comparable to actual trials.
This is a plain-language methodology definition for reading research. It is general education, not medical advice.