The entry presents an example of collaboration across systems based on shared principles and an exemplar of a principles-based developmental evaluation. The collaboration consists of a family foundation convening six nonprofit organizations that serve homeless youth in a metropolitan area. The collaborative approach was based on the assumptions that: youth's different needs are met by different agencies; what constitutes effective programming varies depending on the age, history, and situation of the youth; and the providers are operating within a complex adaptive system. A multiple case study method was selected to investigate how these principles were employed and experienced by multiple stakeholders within the system. A systems inquiry framework was applied to the design and analysis. About me: I have an MA in Research Methods and a PhD in Evaluation Studies. My experience as an evaluator and researcher includes work with schools, school districts, local community organizations, national nonprofits and government entities. #developmentalevaluation #Principles