# Emulate the trial in real-world data first to decide which trials to run

Source: https://onco.cc/ideas/idea-tr1-target-trial-emulation-to-prioritise-rcts/  
OnCo record `idea-tr1-target-trial-emulation-to-prioritise-rcts` (Idea). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Before spending millions on a randomised trial, analyse existing patient records as if the trial had already happened. If the answer is obvious or the question is unanswerable, skip or redesign the trial.

## Summary

Funders require a target-trial emulation in linked EHR or registry data as part of any application for a comparative-effectiveness trial: the emulation estimates the likely effect size, event rates, eligible population and recruitment feasibility, and identifies confounders to stratify on. Trials proceed where emulation is inconclusive or where residual confounding is plausible; the emulation also serves as a pre-registered comparator for the trial's result.

## Fields

- Kind: Idea
- Last checked: 2026-09-08
- Hypothesis: Trials prioritised by emulation will have a higher rate of informative (positive or clearly negative) results and lower rates of underpowered or unfeasible studies than trials prioritised by expert opinion alone.
- Rationale: Target-trial emulation has reproduced randomised results in several therapeutic areas when done carefully; it is cheap relative to a trial and improves design assumptions (event rates, effect sizes) that commonly fail.
- Proposed test: A funder runs emulations for all comparative-effectiveness proposals over two funding rounds and follows the completed trials for informativeness versus the previous rounds.
- Maturity: early-clinical
- Actor: data

## Sources

- Bottleneck evidence (Trial design, endpoints and cost): Davis et al., Availability of evidence of benefits on survival and quality of life of cancer drugs approved by EMA 2009-13 (BMJ 2017): https://doi.org/10.1136/bmj.j4530

## Connected records

- collections: [AACR Project GENIE](https://onco.cc/collections/genie/), [SEER (Surveillance, Epidemiology, and End Results)](https://onco.cc/collections/seer/)
- terms: [Real-world evidence](https://onco.cc/terms/real-world-evidence/)
- bottlenecks: [Funding follows fashion, not burden](https://onco.cc/bottlenecks/b-funding-allocation/), [Trial design, endpoints and cost](https://onco.cc/bottlenecks/b-trial-design/), [Weak real-world evidence and registries](https://onco.cc/bottlenecks/b-real-world-evidence/)
- key papers: [Availability of evidence of benefits on overall survival and quality of life of cancer drugs approved by European Medicines Agency: retrospective cohort study of drug approvals 2009-13](https://onco.cc/key-papers/paper-davis-bmj/)
- roadmaps: [Trial modernisation roadmap: the randomised trial → platforms and adaptive designs → decentralised, pragmatic and always-on](https://onco.cc/roadmaps/trial-modernisation-roadmap/)

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