Based on recommendations from the advisory group, the selection of sites included two levels of screening: the characteristics that each individual authorizer should have in order to be included and the overall characteristics of the pool of authorizers.

In order to be considered, each individual authorizer had to meet the following criteria: 1) strong performance of the schools chartered by the authorizer, as compared to traditional schools within its jurisdiction; 2) some impact on public education in their jurisdiction; 3) experience responding to school failure, school renewal issues, or both; and 4) evidence that the authorizer engages in the effective practices outlined in the conceptual framework.

Once individual authorizers were assigned a rating based on these criteria, they were then sorted by various characteristics that the advisors felt should be represented in the overall pool of authorizers to be included in the guide. These "pool" characteristics included: 1) diversity by type of authorizer (ideally including one or two local school boards, a college or university, a nonprofit organization, a state-level board, a special-purpose charter board, and a mayor or city council); 2) diversity by volume of authorizing; and 3) diversity of authorizing approaches (to the extent this can be ascertained in the screening process). The advisors also urged having a balance between well-known authorizers and "rising stars" and to consider geographic diversity.

The final pool of sites was determined by selecting eight high-scoring authorizers who collectively create the desired diversity in the case study pool, as outlined above.

A two-day site visit was conducted to each of the case study sites. Semi-structured interviews were supplemented with more informal conversations with a range of stakeholders—authorizer staff, school site administrators from at least two schools, and evaluators. An interview protocol was developed based on the study framework and adapted to each role group. That is, separate but overlapping sets of questions were developed for authorizer staff, school site staff, and others. Key interviews were tape-recorded to ensure lively descriptions and quotes using natural language. A written survey was used to collect standard quantitative information, such as number of schools, and renewal rates. While conducting the case studies, staff also obtained copies of local documents, such as applications, review criteria, outreach materials, and site visit protocols.