Researchers and practitioners concerned with STEM learning (science, technology, engineering, and mathematics) occurring outside the institutional boundaries of schools recognize the need for assessment approaches that accommodate the characteristics of informal learning. These approaches, to be viable, must align with the activities, goals, roles, and outcomes we find in informal settings. A plausible starting point is in making use of naturalistic assessments--people's own ongoing, developing awareness of who can do what under which circumstances. People regularly and informally assess one another to shape and support learning activities, goals, and outcomes. This article seeks to make a case for developing a new research program for assessing learning outcomes by capitalizing on people's everyday attunements, which are already in place, and by getting more value out of the cultural apparatus that exists for recognizing one another's capabilities. [ABSTRACT FROM AUTHOR]