The objective of this study was to identify relevant outcomes and measures to inform a systematic review (SR) on the comparative effectiveness of geriatrician-led care models. Study Design and Setting: In the modified Delphi to select outcomes for inclusion in the SR, knowledge users (KUs) from Ontario, Alberta, and Saskatchewan rated outcome importance using a Likert scale. A survey was then completed by geriatricians to determine optimal measures for selected outcomes. Findings were analyzed using frequencies, means, and standard deviations (SDs). Results: Thirty-three KUs (patients, caregivers, policymakers and geriatricians) rated 27 outcomes in round 1 of the modified Delphi. Top-rated outcomes included function (mean 6.85 6 SD 0.36), cognition (6.47 6 SD 0.72), and quality of life (6.38 6 SD 0.91). Twentythree KUs participated in round 2 and rated 24 outcomes. Top-rated outcomes in round 2 were function (6.87 6 SD 0.34), quality of life (6.45 6 SD 1.10), and cognition (6.43 6 SD 0.73). The survey was completed by 22 geriatricians and the highest ranked measures were Activities of Daily Living (function), Mini-Mental State Examination (cognition), and the Medical Outcomes Study SF-36 (quality of life). Conclusion: We identified the most relevant outcomes and measures for patients, caregivers, policymakers, and geriatricians, allowing us to tailor the SR to KU needs.