The Prague 2025 consensus checklist for reporting indirect outcome studies of Model 1b analytical performance specifications

Objectives Analytical performance specifications (APS) based on the Milan Model 1b criteria investigate the impact of analytical performance of a test on clinical classification or decisions, as indirect intermediates to health outcomes of patients. In the lack of guidance for how Model 1b APS should be developed, the objective was to provide generic methodological standards for the design, conduct and reporting of indirect outcome studies for Model 1b APS. Methods An interactive workshop followed by several online meetings of experts was organised to discuss the key challenges and limitations of and to develop a checklist of essential reporting elements for Model 1b APS studies. Results The checklist for reporting Model 1b APS includes 17 essential items with explanatory notes and cross-references to 25 items of the 2025 STAndards for Reporting Diagnostic accuracy studies using artificial intelligence (STARD-AI). Conclusions The checklist of essential reporting items will assist the systematic development of Model 1b APS by various statistical or simulation models and ensure that the Model 1b APS are scientifically valid, robust and transferable across different settings and applications in health care.