The CPDO universe of 1,015 offices included all public defender offices that were principally funded by state or local governments and provided general criminal defense services, conflict services, or capital case representation. Offices that provided primarily contract or assigned council services with private attorneys, were privately-funded or principally funded by tribal or federal government, or provided primarily appellate or juvenile services were outside the scope of the project and were excluded. The included offices generally fit into one of three categories of public defender system: 1. state- funded and administered (state); 2. county- funded and administered (county); and 3. county-based but with the state providing some degree of funding or oversight (hybrid). Offices within the state systems functioned entirely under the direction of a central administrative office, while the county and hybrid offices were at least partially autonomous.  These variations in public defender systems dictated the manner by which the CPDO data collection instrument was distributed. For the 27 county and hybrid states with 763 individual offices, each office submitted one completed questionnaire via a paper or online submission method. The 22 states with a central state-based public defender office completed an online questionnaire and responded to questions pertaining to each of the 483 local offices within the states. Since the state-based offices often shared resources among the local offices as needed, the state-based offices were given the option of providing data on staffing, caseload, and expenditures for either the entire state or for each local office. Though a handful of states were able to provide staffing, caseload, and expenditure data at the office level, the majority of states could only provide state-level data for these three important measures. Thus, all data from the 22 states were aggregated to the state-level for the analysis. The CPDO data collection instrument was developed through collaboration among BJS, the data collection agent, the National Legal Aid and Defender Association (NLADA), and a number of chief defenders and indigent defense scholars. The instrument was additionally sent to the American Bar Associations Standing Committee for Legal Aid and Indigent Defense and the National Association of Criminal Defense Lawyers for review and comment.

While the CPDO exclusively examined public defender offices, future surveys addressing public defense are likely to include other indigent defense delivery systems including assigned counsel and contract programs.