Educators, education researchers, and policymakers have increasingly pointed to the importance of advanced coursework to prepare high school students to enter and succeed in college. Research has found ample evidence of the importance of such coursework, which can include Advanced Placement (AP) and International Baccalaureate (IB) courses. The positive advantages of taking such coursework appears to accrue while students are in high school and to increase their likelihood of entering and succeeding in postsecondary education (Coca et al, 2012; Conger et al., 2021; Perna et al., 2015).

             Unfortunately, access to advanced coursework is not uniform across students or schools in the United States. Studies of access to IB coursework have found that despite growing efforts by the International Baccalaureate Organization to expand and “democratize” IB course offerings, lower-income and ethnic minority students do not have equal access to them (Perna et al., 2015). There is also evidence that both IB and AP coursework are less available to students in remote and rural schools, relative to students in cities and suburban areas (Gagnon & Mattingly, 2016; Thier & Beach, 2021). However, because IB is offered on a much smaller scale than AP, IB courses are much less common than AP courses in rural schools (Thier & Beach, 2021). Assuming that IB and AP programs provide a clear advantage over non-advanced coursework, this pattern has negative implications for the educational achievement and attainment of students in rural areas, as well as for rural development (Saw & Agger, 2021).

             Despite the clear advantages of advanced coursework for students’ high school and postsecondary success, it is not clear whether all advanced coursework has the same benefit for students. Many studies that examine the link between advanced course-taking and student success combine AP and IB into one group, as if they offered the same educational experience and rigor (e.g., Long et al., 2012). In fact, there are important differences between AP and IB in their missions, structures, and potential utility for high school students (Saavedra, 2014; Thier & Beach, 2021). For example, whereas AP offers discrete, subject-based courses, IB provides a comprehensive program of study leading to an internationally recognized high school diploma. Further, IB’s emphasis on global understanding may offer an additional benefit to students in rural areas, who have less opportunity to develop “international mindedness” than their peers in large cities (Thier & Beach, 2021). Unfortunately, very few studies have directly compared the relative impact of AP and IB coursework on students’ high school and postsecondary success.

Our objective is to examine differential access to and impact of advanced coursework—specifically IB and AP courses—for high school students across communities of different sizes (urban, suburban, town, and rural) in the United States. Although AP and IB are commonly grouped together under the category of “advanced coursework,” we examine differences between these two curricular and programmatic approaches in terms of availability, course-taking, and impact on high school and post-secondary outcomes. Using data from the US National Center for Education Statistics’ High School Longitudinal Study (HSLS 2009), which allow us to generate nationally representative results, we examine the following research questions:

1. Does access to AP and IB courses vary across schools in communities of different sizes (urban, suburban, rural, towns) in the United States?
2. How do students in these schools differ in terms of whether and which advanced courses they take?
3. Do students in these schools differ in terms of the relative impact of AP and IB courses on their high school achievement and post-secondary outcomes?

For our analysis, we draw on the rich, nationally representative HSLS:09 data, administered by the NCES. NCES also conducted HSLS follow-up studies in 2012, 2013, and 2016. We also use data from the HSLS high school and postsecondary transcript studies, generated in 2013 and 2017 respectively. Together, these data allow us to examine and compare AP and IB courses in terms of high school- and college-level outcomes. To conduct our analysis, we must contend with the fact that students are not randomly assigned to AP or IB programs. In fact, many schools have entry requirements, such as a minimum GPA or test score performance, for students to enroll in these courses in the first place (Saavedra, 2014). This suggests the possibility of pre-existing differences between program participants and non-participants, leading to sample selection bias (Dickson et al., 2018). Further, neither AP nor IB programs are evenly distributed across urban and non-urban schools, nor do these programs uniformly enroll students within schools. We employ several strategies to mitigate the potential for sample selection bias in our estimates. First, we first limit our analytic sample to 12th graders in 2013 who ever participated in either AP or IB programs only. This approach allows us to: (1) directly compare the relative effectiveness of each of these programs and (2) reduce or eliminate the first type of bias, between program participants and non-participants. Second, we use a differences-in-differences (DID) approach to account for between-school bias. Using the DID approach, we subtract differences in the outcomes of AP students between urban and non-urban areas from differences in the outcomes of IB students between the two areas. The underlying idea is to cancel out any pre-existing differences in characteristics, whether observed or unobserved, of IB and AP students and programs between urban and non-urban schools. Last, we introduce propensity score matching to adjust for any remaining pre-existing differences between IB and AP participants based on the observed characteristics of individuals. We then replicate a differences-in-differences estimation for matched samples of IB and AP students between urban and rural schools. To test the robustness of our results, we employ other propensity score methods including propensity score stratification and inverse probability weighting.

For Research Question 1, we find that although IB and AP courses are both less likely to be offered in towns and rural areas relative to cities, the differences between towns/rural areas and cities are much greater in terms of IB availability. However, when schools do offer IB courses, students are more likely to take them, compared to AP students. The results of Research Question 2 adds evidence to these conclusions. When examining course-taking patterns of students in schools that offer both IB and AP courses, we find that students take on average more IB units. Finally, our findings regarding the relative impact of IB and AP courses on students’ high school and postsecondary outcomes (Research Question 3), we find that whereas IB students in towns have a small advantage in high school-level outcomes (primarily in terms of GPA in IB/AP courses), IB holds a consistent advantage in terms of postsecondary outcomes for students in towns and rural areas. These include enrollment in a four-year college (towns and rural areas), credits earned in the first year of college (rural areas), first-year GPA (rural areas), total credits (rural areas), and accumulated GPA (rural areas). However, our analysis finds systematic differences between IB and AP students that are driven primarily by school-level supply constraints. After adjusting for these differences by limiting our sample and applying propensity score matching, we continue to find a relative IB advantage for students in towns and rural areas in terms of IB/AP GPA (towns), four-year college enrollment (rural areas) and accumulated GPA (towns). Our sensitivity analysis using propensity score stratification and inverse probability weighting finds similar results, suggesting that our key findings related to IB advantages for town and rural students are robust across different specifications for 12th grade GPA, four-year college enrollment, and accumulated college GPA.

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