To expand participation in Advanced Placement (AP) courses, several District of Columbia Public Schools (DCPS) high schools have enacted a policy mandating that all students enroll in one or more AP courses. To promote quality instruction in AP courses, DCPS recommends regular teacher participation in the Advanced Placement Summer Institute (APSI) and is considering recommending that teachers' college major be factored into teacher assignments to AP courses. To better understand this policy and these recommendations, this study examined students' AP exam taking and passing rates in schools that mandate AP course enrollment and in schools that do not, teacher participation in the APSI, and the alignment of AP teachers' college major with the AP course they teach. Three of the four high schools that adopted a mandate on AP course enrollment during the study period had higher AP exam taking and passing rates after their mandate went into place. In three of the five schools that adopted a mandate before or during the study period, the passing rate (grade 10-12 students in the school who passed at least one AP exam as a percentage of all grade 10-12 students in the school) was below 20 percent in every year of the study period, and in a fourth it was below 50 percent in every year. Fewer than one-fifth of AP teachers participated in the APSI at least once every three years. Participation rates were higher in schools offering more AP courses, in schools with lower percentages of racial/ethnic minority students, among teachers whose college major aligned with the AP course they taught, and among more experienced teachers. Among AP teachers with a college major on record, about half had a college major aligned with each specific AP course they taught, and 70 percent had a college major aligned with the broad subject area of each AP course they taught. [For the study snapshot, see ED611754. For the appendices, see ED611755.]