Researchers increasingly recognize that stakeholder involvement enhances research relevance and validity. However, reports of patient engagement in research that relies on administrative records data are rare. The authors' collaborative project combined quantitative and qualitative studies of costs and access to care among U.S. adults with employer-sponsored insurance. The authors analyzed insurance claims to estimate the impacts on enrollee costs and utilization after patients with bipolar disorder were switched from traditional coverage to high-deductible health plans. In parallel, in-depth interviews explored people's experiences accessing treatment for bipolar disorder. Academic investigators on the research team partnered with the Depression and Bipolar Support Alliance (DBSA), a national advocacy organization for people with mood disorders. Detailed personal stories from DBSA-recruited volunteers informed and complemented the claims analyses. Several DBSA audience forums and a stakeholder advisor panel contributed regular feedback on study issues. These multiple engagement modes drew inputs of varying intensity from diverse community segments. Efforts to include new voices must acknowledge individuals' distinct interests and barriers to research participation. Strong engagement leadership roles ensure productive communication between researchers and stakeholders. The involvement of people with direct experience of care is especially necessary in research that uses secondary data. Longitudinal, adaptable partnerships enable colearning and higher-quality research that captures the manifold dimensions of patient experiences.