All projections are based on the number of state funded students ( P-223 count) and created from trending data over past years (including progression ratios, show rates, and the Birth-to-K ratio).

From the resident projections, enrollment within attendance area schools is modeled, taking into account option school seats, and program choices for students, program eligibility, and other factors.

First, resident enrollment in the district is modeled over the past 10 years, and modeled based on the residence of students. This requires not only past enrollment, but also recent birth data for Seattle, from the Washington State Department of Health.

Enrollment Planning produces three types of projections:

• the 10 year resident projection, of all students residing and enrolled in the district, but not based on where in SPS they attend;
• the school enrollment projection for October of the upcoming school year; and
• the school enrollment projection for October of the next 5 years

Enrollment Planning takes into consideration housing information, major employers, city planning projects, and other socioeconomic factors in Seattle when calculating projections.

For schools that are homeroom-based (K-5s and K-8s), projections are modeled with expected classroom configurations for that school.

If the number of classrooms is correct and there are additional seats available, those seats will be filled in accordance with demand (i.e. if there is a waitlist) and without negative impact to that school’s staffing. In other words, Enrollment Planning will fill empty seats in classrooms, rather than restricting enrollment to the number of initially projected students.

There will be some degree of variance between the projected headcount forecasted in the spring and the actual headcount recorded in October.

The progression ratio is the year over year historical cohort advancement data (from Kindergarten to 1st grade, 1st grade to 2nd, etc.). This ratio removes data outliers, is typically within one standard deviation, and is applied to the expected number of students anticipated from resident projections.

The number of assigned students varies from month to month throughout the school year. A school’s show rate reflects attrition or growth in assigned students between a given time (e.g. July 1) and the October 1 enrollment head count. As October approaches, the show rate becomes closer to 100%. If a school’s show rate indicates losses over the summer, this is based on historical data, and has been adjusted for the actual numbers each year.

The Washington State Department of Health provides the district with birth data for the City of Seattle. From this information, Enrollment Planning determines the number of births in each elementary attendance area school boundary who will attend their neighborhood school for kindergarten five years later, adjusting for the percentage of those who historically move in and out of each boundary.