What a policy pilot can earn permission to scale

A pilot can establish delivery feasibility without resolving effectiveness, additionality, or performance at scale. This methods note develops a reading procedure for a hypothetical repair-voucher programme using the Magenta Book, the CONSORT pilot-trial extension, and Deaton and Cartwright’s methodological analysis. It distinguishes invitation, enrolment, use, repair completion, and sustained service, and explains selection, intention-to-treat comparisons, missing data, uncertainty, and transportability. The fictional planning case contains no completed trial or measured outcomes. Scaling questions include repairer capacity, upfront-payment barriers, changing costs, and different participant populations. No policy saving or climate effect is estimated. The practical implication is to match progression decisions to the pilot’s learning objective, pre-specified criteria, ethical constraints, and the supporting conditions a larger programme would require.