Ethnography contributes to measure development by enhancing validity and providing a basis for qualitative validation. Validating research measures means making cases for their "trustworthiness." The authors argue for the trustworthiness of CONNECT, a measure of continuity of care, by presenting the interpretive logic through which they elaborated continuity for measure construction purposes. They used category construction methods to identify mechanisms of continuity in ethnographic data. Mechanisms suggested five measurement domains: (a) knowledge, (b) flexibility, (c) availability, (d) coordination, and (e) transitions. Validation rationales summarize the ethnographic evidence and explain how the domain relates to continuity. In making explicit the data and the reasoning used, the authors argue for the trustworthiness of their interpretation. The arguments for trustworthiness demonstrate a qualitative validation process.