Student Population Projections

Generating Student Population Projections in Nashville & Davidson County

The Metropolitan Planning Department of Nashville and Davidson County has developed a new method for generating student population projections. The student population projections will provide both the School Board and the Planning Department with more accurate information that will be useful in planning for new schools and when they will need to be built to meet the growing demands of the community.

In order to determine a new method for generating student population projections two goals were established. First, the student population projections would be based on high school clusters (eleven) instead of using a countywide approach. A high school cluster is a group of elementary and middle schools that feed into one high School. A specific set of student generation rates for each high school cluster would more accurately depict the number of students being generated in that area. Previously, we were using the same generation rates for all the high school clusters. Second, the process for calculating the student generation rates would have to be practical enough that it could be updated on a yearly basis. Using the process described below accomplishes both goals. All the analysis was generated using ArcGis 8.1 and the examples in this article are for the Antioch High School cluster a rapidly growing area in southeast Davidson County.

1. The first step of the process was to compile a geo-coded shapefile detailing each student's address and grade. Once we had this shapefile we were able to do a spatial join to our property polygons layer file. After the files were joined we were able to determine the land use code for each student and classify them as being either single-family or multi-family housing type. This attribute allows us to calculate the number of students living in single-family housing and the number of students living in multi-family housing. For example in the Antioch High School cluster 74% of the students live in single family housing and 26% live in multi-family housing.

2. The second step was to make a shapefile of all the single and multi-family housing in Davidson County. This makes it easier to query single and multi-family housing units for the area being analyzed. For example, the Antioch High School cluster has 15,238 single-family homes and 15,320 multi-family units.

3. The third step was to add up the number of students in the elementary, middle, and high schools. In this case we had 4,095 elementary school students, 2,862 middle school students, and 2,326 high school students. We then multiply these totals by the percentage of students living in single-family housing and the percentage of students living in multi-family housing.

4. The last step is to divide the number of students living in single-family housing by the number of single-family homes; and divide the number of students living in multi-family housing by the number of multi-family units. This will give us the student generation rates for elementary, middle, and high school students in single-family and multi-family housing.

What this shows is that in the Antioch High School cluster for every 100 single-family houses there are 20 elementary school students, 14 middle school students and 11 high school students and for every 100 multi-family units there are 7 elementary school students, 5 middle school students, and 4 high school students. Then if we forecast the number of building permits and we know that in 5 years we expect 2920 new single-family homes and 1000 new multi-family homes we will be able to determine how many students these additional homes will generate. Using the ratios listed in the above example we can expect 650 additional elementary school students, 455 additional middle school students, and 370 additional high school students.