Mobility Factors

Calculating Mobility Factors

Student mobility factors further refine the resident student forecasts. Mobility factors represent the net effect of the migration of students into and out of the district from existing homes. These factors help account for housing resales, renter migration, private school transitions, and high school drop-outs. If you have at least four consecutive years of geocoded student data (which represents three years of enrollment change), the mobility factors can be calculated down to the study area level. The factors are derived from comparing student counts in study areas where there has been no new residential development for the past four years. (This is to avoid double counting students moving in due to new housing construction which are accounted for in the tract dataset.)

In cases where historical geocoded student data is not available, mobility factors can be calculated using historical enrollment reports (i.e. the District’s standard annual fall reporting period) although this is not the preferred method. If you only have hard copy enrollment reports by school, mobility factors can only be generated by attendance area or district wide. If comparing enrollment at the attendance zone level, be sure that you are comparing data where there has been no boundary changes for the years involved. For best results and a fair comparison, it is recommended that you compare 4 – 5 years of data to have 3 – 4 years of changes.

Please Note: If the mobility factors are calculated based on enrollment reports, this does NOT mean your forecasts reflect the enrollment forecasts at each school. The final forecasts still represent the forecasted students by residence.

Mobility is calculated for each grade in the district. Comparison is made between students in one grade with the numbers of students in the next grade the following year. For example, if your historical data begins in 2010, you would compare the total Kindergarten students of 2010 with that of 1st grade students of 2011 (the next year of students). All things being equal and with no new development in the area of comparison, the number of 1st grade students should be equal to the Kindergarten class from the year before assuming they all moved up a grade and stayed in the same area.

Please Note: In general, mobility factors should have a tendency to vary closely to 1.00 unless there are extreme drop-outs or movement from private schools or other factors. If your calculated mobility factors are extremely higher or lower than 1.00, you may wish to check your enrollment counts and/or factor calculations. If hard copy enrollment reports by school are used (due to the fact you do not have historical geocoded student data), you should be careful of your calculations for schools in areas that have had attendance boundary changes as these would have a tendency to skew your calculations.