Primary care providers are experiencing increasing pressure to use evidence based practice guidelines to validate their clinical decisions.  In some areas third party reimbursement is contingent upon proof that practice guidelines are followed.  Existing evidence based practice guidelines are focused on mainstream populations and can be a poor fit when applied to underserved groups.  Marginalized groups, such as homeless people or undocumented immigrants, are under represented, if represented at all, in the evidence based practice literature.  People who engage in covert behavior such as sex workers or drug users depend upon remaining elusive; therefore, these intentionally invisible populations have no voice in health care practices that reinforce health disparities.

This paper describes a Participatory Action Research approach that was used to develop a nursing clinic serving an urban homeless population. Clients had direct ongoing access to the investigator and students who worked with them, creating and implementing health promotion and disease prevention outreach activities, monitoring their outcomes, and modifying offerings in response to clients’ feedback.  Clients determined what health issues they were willing to address and how to work with staff in addressing these issues.   They decided what constituted credible evidence and how it could best be gathered and used.  Clients generated practice guidelines congruent with their unique lifestyles, and tracked the outcomes of evidence based care delivered throughout a three year period.