Linking Tax Lot and Student Record Data for School Planning

The Population Research Center at Portland State University is the demographic consultant to Portland Public Schools. Changes in student demographics are, to a large degree, driven by changes in the types of housing in the district and by who lives in that housing. For that reason, student and tax lot records are linked to be able to examine the effects of housing variables, such as tenure, number of bedrooms, and housing values, on the composition of the district's school-age population. Knowing these linkages also facilitates communication between school and community planners. The area shown includes many low-income and minority households living in crowded conditions. The color-keyed areas suggest some relationships between tenure, minority status, and number of bedrooms.

The tax lot and student record databases are linked using a "near function." Characteristics of students, such as their age and race, can be linked to characteristics of the residence where they live such as tenure and type of structure.

One application shows a point for each student living in single-family housing built in the 1991–2000 period and a color shading showing the proportion of the district's students living in such housing. Only a few areas show more than 5 percent of the district's students living in 1990s single-family housing. While there has been a substantial amount of infill and replacement housing, most of it has accommodated families without children.

A second application shows the average number of students per housing unit by tenure for owner- and renter-occupied housing. The maps show that there are more students per unit in renter-occupied housing than owner-occupied housing. In addition, there is considerably more geographical variability in the numbers in renter-occupied housing than in owner-occupied housing. One reason for the decline in student enrollments in the district has been the conversion of renter-occupied homes to owner occupancy.