Urban mobility and the experienced isolation of students

Abstract

Cities provide access to stores, public amenities and other people, but that access may provide less benefit for the lower-income and younger urbanites who lack money and means of easy mobility. Using detailed GPS location data, we measure the urban mobility and experienced racial and economic isolation of the young and the disadvantaged. We find that students in major metropolitan areas experience more racial and income isolation, spend more time at home, stay closer to home when they do leave, and visit fewer restaurants and retail establishments than adults. Looking across levels of income, students from higher-income families visit more amenities, spend more time outside of the home, and explore more unique locations than low-income students. Combining a number of measures into an index of urban mobility, we find that, conditional on income, urban mobility is positively correlated with home neighborhood characteristics such as distance from the urban core, car ownership and social capital. For over 50 years, social scientists have documented urban residential segregation 1,2 , and its pernicious effects, particularly for children 3-7. More recently, Athey et al. 8 demonstrated that experiences are not perfectly delineated by place of residence, finding that 'experienced isolation' is far lower than residential segregation, building on the 'activity space' literature in sociology 9-14. Browning et al. 15 similarly finds that Black youth experience more inter-racial interactions than implied by residential location alone. Interaction with a diverse set of people is only one potential benefit of urban life. In this Article, we examine a range of outcomes, including racial and income-based experienced isolation, visits to urban amenities , exploration of new places and distance traveled, using a panel of location data from GPS-enabled devices. We are particularly interested in the lives of younger urbanites. Recent work has shown that children in denser urban areas experience less upward economic mobility 16 , despite access to a range of amenities, public goods and social infrastructure offered by cities. At the same time, past decades have seen a rise in income segregation for households with children, but not for childless households 17. Although we cannot identify the sources or consequences of these developments, both are informed by how youth interact with their neighborhood and/or broader urban environment. In this Article we build a panel of location data from GPS devices and infer three characteristics for each device: household income, race and student status. To infer income, we follow Cook 18 and match each device to its home parcel, then use characteristics of the home (for example, market value, structure age and location) to predict income. For race, we follow Athey et al. 8 and use whether or not a device is from a majority non-Hispanic white block group to define 'White' and 'non-White' devices. Finally, we define 'students' as 16-18-year-olds attending school and infer student status from whether an individual's most common weekday location is a high school. For privacy reasons, mobile-phone record providers remove anyone under 16 years of age. Importantly, this sample contains a mixture of high-school students, teachers and staff, which probably attenuates the differences we measure between students and adults. Furthermore, US teachers are disproportionately White relative to their students; during the 2017-2018 school year, in public schools where the majority of students were Black, 54% of teachers were White 19. Nonetheless, we find consistent and meaningful gaps in the urban mobility and isolation of students versus adults. We also perform several robustness checks, as well as a back-of-the-envelopment bias correction that suggests the impact of teachers is small, in Supplementary Sections A and B. We start by estimating the day-today experienced isolation across both race and economic lines. Following the methodology of Athey et al. 8 , we find that students experience more racial and income isolation than adults. Excluding time spent at home, the racial isolation of students is 21% higher than that of adults in the 100 largest metropolitan areas. The income isolation of students 13% higher than that of adults, driven