# What is the sparsity size adjustment?

What is the Sparsity/Size Adjustment and how is it calculated? There is one final category of “add-on” ADMs in the BEF formula: the sparsity/size adjustment. The sparsity/size adjustment is a factor that was carried over from the state’s special education funding formula, and its purpose is to recognize that some school districts can’t benefit from economies of scale, and thus, have increased educational costs as a result.

The sparsity/size adjustment applies to a limited number of school districts—just 150 each year. To be eligible to receive ADM add-ons based on this factor, a school district has to be very large geographically AND very small in total population.

The two components of this measure are:

A size ratio—which measures how a school district’s total ADMs compares to the state average of total ADMs (districts that are smaller than the state average ADMs may qualify for the adjustment)

A sparsity ratio—which measures each school district’s ADMs per square mile in comparison to the state average ADMs per square mile (districts that have fewer ADMs per square mile than the state average may qualify for the adjustment)

These two ratios are combined, and only the districts that are above the 70th percentile of all districts (i.e. the smallest in population and most spread out districts) get some add-on ADMs for this factor. The amount of add-on ADMs they get is dependent on how much above the 70th percentile they are—some of the eligible school districts get a minimal add-on, while others get in excess of 150 additional ADMs.

The sparsity/size adjustment for each qualifying school district is calculated by dividing the school district’s sparsity/size ratio by the ratio at the 70th percentile and then subtracting 1. The formula then multiplies this result by the sum of the student components (poverty, English language learner, and charter school weighted ADMs) and core 3-year average ADMs. Finally, this result is multiplied by 0.7 which results in the add-on ADMs for that schools district.

For example, Tussey Mountain SD's sparsity size adjustment is calculated by taking their sparsity size ratio of 0.8805 and multiplying by 0.7572 and subtracting 1. The result is then multiplied by 1,166.05 and 0.7, resulting in 132.91 additional ADMs.

Click on the map below to review the school districts that receive add-on ADMs (and the amount of the add-ons) as a result of the BEF’s sparsity/size adjustment.