Do Bus Transfers in School Commutes Harm Student Attendance and Academic Outcomes?

Burdick-Will and Stein (2026) ask how commute complexity, especially bus transfers, affects high school students’ attendance, school mobility, and academic performance. They analyze administrative data on all Baltimore City high school students in 2016–17 and 2017–18, exploiting a system-wide transit overhaul as a natural experiment. They find that total travel time has no meaningful effect on outcomes, but requiring a bus transfer increases absenteeism and school switching. Specifically, students with a transfer are several percentage points more likely to be absent and to change schools. They conclude that commute complexity, not duration, is the key mechanism affecting student engagement and stability.

Why This Article Was Selected for The Policy Scientist

This article addresses a policy issue with broad relevance: how access to reliable transportation shapes educational engagement in urban systems. As districts expand school choice while reducing dedicated bus services, student commutes are becoming more complex, making this question increasingly salient. Burdick-Will has an established record in this domain, and this study advances that literature by isolating commute complexity from travel time. The timing is notable given national shifts toward public transit reliance and logistical strain in school transportation. The administrative dataset is comprehensive and well-suited to the question, though limited to one city. The quasi-experimental design using route fixed effects represents a meaningful step toward causal inference, though future work using stronger identification strategies would further strengthen confidence.

Full Citation and Link to Article

Burdick-Will, J., & Stein, M. L. (2026). Changing buses: Commute complexity and academic outcomes. Education Finance and Policy. https://doi.org/10.1162/EDFP.a.446

Central Research QuestionThis article investigates whether and how the difficulty of students’ daily commutes—specifically the distinction between total travel time and route complexity—affects key academic outcomes. The central research question is whether more complex commutes, particularly those requiring bus transfers, causally influence student attendance, school mobility, and grade point average. The study is motivated by a policy environment in which school districts increasingly rely on public transportation rather than dedicated school bus systems, thereby introducing greater variability in how students travel to school. A core conceptual contribution is the separation of commute duration from commute structure, allowing the authors to test whether unpredictability and logistical coordination, rather than time spent traveling, drive educational consequences. The analysis focuses on whether students exposed to more complex transit routes exhibit measurable declines in engagement and stability within the school system.

Previous LiteratureThe article builds on a relatively recent but expanding body of research linking transportation barriers to educational outcomes. Prior studies have primarily focused on commute length or eligibility for school-provided transportation, often finding that longer commutes are associated with higher absenteeism and increased likelihood of school transfers. However, these studies face significant identification challenges due to selection bias, as families typically choose schools and thus implicitly select commute characteristics. Moreover, much of the literature has concentrated on traditional school bus systems, which are comparatively predictable and do not capture the complexities of public transit. The authors position their work as addressing two central gaps: the inability to disentangle causal effects from selection processes and the lack of attention to alternative transportation modes that introduce complexity. While earlier quasi-experimental work—such as studies exploiting eligibility cutoffs—has improved causal inference, it remains limited in scope. This study extends that literature by examining public transit-based commutes and introducing route complexity as a distinct and theoretically meaningful dimension.

DataThe empirical analysis relies on comprehensive administrative data from Baltimore City Public Schools, covering all high school students during the 2016–17 and 2017–18 academic years. These data include detailed student-level information on demographics, enrollment, attendance, grade point averages, and school mobility. The dataset is notable for its breadth, encompassing approximately 39,300 students across 36 schools, and for its integration with geospatial information on student residences. This allows the authors to construct highly granular estimates of commuting patterns. To measure commute characteristics, the study employs transit routing software using official schedule data from the Maryland Transit Administration, generating estimated travel times and identifying whether routes require transfers. These estimates are linked to students based on their residential location and enrolled school. The dataset’s comprehensiveness enhances internal validity, though its confinement to a single urban district raises questions about external validity, particularly for suburban or rural contexts with different transportation infrastructures.

MethodsThe study employs a quasi-experimental design that exploits a major overhaul of Baltimore’s public transit system (BaltimoreLINK) as a source of exogenous variation in commuting conditions. This redesign altered bus routes and schedules in ways that changed travel time and route complexity without affecting students’ residential locations or school assignments. The authors use route fixed effects to compare students who share the same origin–destination pair but experience different commute characteristics across years due solely to the system changes. This approach effectively controls for unobserved, time-invariant factors related to both neighborhood and school choice, addressing a central limitation of prior research. The empirical model incorporates student-level covariates and year-by-grade fixed effects, with standard errors clustered at the route level. While the design represents a strong quasi-experimental strategy and approximates causal inference, it does not reach the evidentiary standard of a randomized controlled trial. Nonetheless, the plausibly exogenous nature of the transit changes and the within-route comparisons substantially strengthen causal interpretation relative to conventional observational studies.

Findings/Size EffectsThe results demonstrate a clear and consistent pattern: commute complexity, rather than total travel time, is the primary driver of negative academic outcomes. Specifically, the presence of a bus transfer is associated with statistically significant increases in absenteeism and school mobility. Students whose commutes require a transfer are several percentage points more likely to be absent and to change schools within the academic year. In contrast, total travel time does not exhibit a meaningful relationship with these outcomes once complexity is accounted for. The absence of effects on grade point average suggests that the primary mechanism operates through engagement and stability rather than direct impacts on academic performance. These findings provide evidence that unpredictability and logistical challenges—such as coordinating multiple transit segments—impose costs that manifest in reduced attendance and increased school switching. The magnitude of the effects, while modest in absolute terms, is substantively important given the scale of urban school systems and the cumulative consequences of absenteeism and mobility for long-term educational attainment.

ConclusionThe article concludes that simplifying student commutes should be a central consideration in transportation and school assignment policy. By demonstrating that complexity—not duration—drives adverse outcomes, the study reframes how transportation barriers are conceptualized within education policy. The findings suggest that policies prioritizing direct routes, even if longer in duration, may yield better outcomes than those minimizing travel time at the expense of requiring transfers. The study contributes to the literature by providing quasi-experimental evidence that isolates a specific mechanism linking transportation to student behavior. While the results are derived from a single urban context, the underlying dynamics of public transit complexity are likely relevant to other cities with similar systems. The methodological approach represents a meaningful advancement, though future research using randomized or more robust causal designs could further validate and extend these findings.bus