Participatory design (PD) can play an important role in obtaining benefits from healthcare information technologies, but we contend that to fulfil this role PD must incorporate feedback from real use of the technologies. In this paper we describe an effects-driven PD approach that revolves around a sustained focus on pursued effects and uses the experience sampling method (ESM) to collect real-use feedback. To illustrate the use of the method we analyze a case that involves the organizational implementation of electronic whiteboards at a Danish hospital to support the clinicians' intra- and interdepartmental coordination. The hospital aimed to reduce the number of phone calls involved in coordinating work because many phone calls were seen as unnecessary interruptions. To learn about the interruptions we introduced an app for capturing quantitative data and qualitative feedback about the phone calls. The investigation showed that the electronic whiteboards had little potential for reducing the number of phone calls at the operating ward. The combination of quantitative data and qualitative feedback worked both as a basis for aligning assumptions to data and showed ESM as an instrument for triggering in-situ reflection. The participant-driven design and redesign of the way data were captured by means of ESM is a central contribution to the understanding of how to conduct effects-driven PD.