Abstract
This article aims to explore the use of the user-centered design (UCD) method, mental model approach, of those who engage in environmental volunteering to work toward the development of a health-related impact measurement tool. It reports a case study which explores the use of one UCD method, a mental model approach. This is an understudied area of research that would be considerably valuable for practitioners in the voluntary sector who wish to create their own health-related impact measurement tool. Focus group interviews are used to explore how volunteers perceive the term health, their conceptual understandings, terminology used, and the attributes to measure it. This study is reported from the perspective of U.K. environmental charity, The Conservation Volunteers (TCV). Findings from this article can be used by other voluntary organizations and charities to help shape their own health-related impact measurement tool and the ways in which these tools can be tailored to suit their individual needs.