Despite the increasing number of protocol and reporting guidelines available to trialists, there is still little guidance for protocol writers on the incorporation of patient-reported outcomes and economic assessments alongside clinical trials. It is unsurprising, therefore, that trial protocols present disproportionately less information for the economic evaluation component than for clinical outcomes. Costing methodologies, generalisability considerations, methods to address sensitive patient-reported outcome information and missing data are often insufficiently described in the trial protocol. The paper illustrates these shortcomings with specific examples and makes a case for shifting researchers' attention from the reporting to the design stage of trial-based economic evaluation to promote the validity, generalisability and accountability of trial-based economic evaluations.