Participatory action research with young people (yPAR) involves youth and adults in a collaborative process of research, reflection, analysis and action. An important part of the research cycle is the identification of a problem definition. Yet, there is relatively little research addressing the process of how young people develop a problem definition on which to focus their analysis and intervention and what methods might exist to facilitate this process. This article draws upon a yPAR project with fifth-grade working-class young people, primarily young people of colour, to demonstrate how the Five Whys method for reflecting on lived experiences facilitated the development of problem definitions in line with second-order change. The Five Whys method, when used within a participatory framework, offers both a context and a structure for young people to critically examine social problems they identify and to seek out root causes. The article highlights changes in the participant's formulation of problems in the context of using the Five Whys method, from a primarily individual level of analysis to a more structural level of analysis. It also outlines the subsequent changes in proposed actions to address the identified problems. Copyright © 2011 John Wiley & Sons, Ltd.