Development and validation of critical appraisal tool for individual participant data meta-analysis: protocol for a modified e-Delphi study.

introductionIndividual participant data meta-analysis (IPD-MA) is regarded as the gold standard for evidence synthesis. However, diverse recommendations and guidance on its conduct exist, and there is no consensus-based tool for the critical appraisal of a completed IPD-MA. We aim to close this gap by systematically identifying quality items and developing and validating a critical appraisal checklist for IPD-MA. METHODS AND ANALYSIS: This study will comprise three phases, as follows:Phase 1: a systematic methodology review to identify potential checklist domains and items; this will be conducted according to the Cochrane methods for systematic reviews and reported following the Preferred Reporting Items for Systematic Reviews and Meta-analysis 2020 guidance. We will include studies that address methodological guides and essential statistical requirements for IPD-MA. We will use the proposed items to prepare a preliminary checklist for the e-Delphi study.Phase 2: at least two rounds of an e-Delphi survey will be conducted among panels with expertise in IPD-MA research, consensus development, healthcare providers, journal editors, healthcare policymakers, patients and public partners from diverse geographic locations with experience in IPD-MA. Participants will use Qualtrics software to rate items on a 5-point Likert scale. The Wilcoxon matched signed rank test will estimate response stability across rounds. Consensus on including an item will be achieved if ≥75% of the panel rates the item as 'strongly agree' or 'agree' and items will be excluded if ≥75% rates it as 'strongly disagree' or 'disagree'. A convenience sample of 10 reviewers with experience in conducting an IPD-MA will pilot-test the checklist to provide practical feedback that will be used to refine the checklist.Phase 3: critical appraisal checklist validation: to improve confidence in the tool's uptake, a subset of the e-Delphi participants and graduate students of epidemiology and biostatistics will conduct content validity and reliability testing, respectively, per the Consensus-based Standards for the Selection of Health Measurement Instruments. ETHICS AND DISSEMINATION: Ethics approval has been obtained from the Western University Health Science Research Ethics Board in Canada. The validated checklist will be published in a peer-reviewed open-access journal and shared across the networks of this study's steering committee, Cochrane IPD-MA group and the institutions' social media platforms.