This paper describes the qualitative component of a large mixed method study, the California Statewide Study of People Experiencing Homelessness. The qualitative study consisted of seven sub-studies across eight counties, each exploring different dimensions of homelessness. BHHI researchers recruited participants from the overall sample, a statewide representative sample of adults experiencing homelessness recruited in eight counties, based on their responses to questions from the survey interviews. The researchers' mereological study design presents an approach for developing complex qualitative policy studies across a range of topic areas.