New Structures:

Select school:

Help Select the school that will be attended by the students at these new residences. APS estimates different effects by each residence for each school. Arlington Analytics does not have different effects by school.




Select area:

Help Select the area that will be attended by the students at these new residences. Arlington Analytics estimates can vary depending on the area of the county of the new construction. Columbia Pike includes planning units: 35070, 36010, 35071, 35072, 36020, 37070, 37060, 35100, 37034, 37033, 37032, 38011, 38010, 37090, 37050, 38030, 38040, 46010, 46022, 46102, 46131, 46130, 46120, 46140, 48280, 46111, 48160, 48281, 48281, 48290, and 48220.




New Single-Family Homes:

Help Choose the number of new single-family homes by the number of bedrooms. The number of bedrooms does not matter for APS estimates; Arlington Analytics effects grow with the number of bedrooms. If old homes are being demolished for the new homes, don't forget to make the number of old homes negative. For example, if a two bedroom were replaced by a five bedroom home, two bedrooms would be "-1" and five bedrooms would be "1".


Two or fewer bedrooms: 

Three bedrooms: 

Four bedrooms: 

Five or more bedrooms: 

New Townhomes:

Help Choose the number of bedrooms for new townhomes. The number of bedrooms does not matter for APS estimates; Arlington Analytics effects grow with the number of bedrooms. For example, if a two bedroom were replaced by a five bedroom home, three or fewer bedrooms would be "-1" and four or more bedrooms would be "1".


Any number of bedrooms: 

New Duplexes:

Help Choose the number of new duplexes. The number of bedrooms does not matter for either APS or Arlington Analytics estimates.


Any number of bedrooms: 

New Garden Condos:

Help Choose the number of new garden condos by number of bedrooms. The number of bedrooms does not matter for APS estimates, however more bedrooms lead to more students on average in Arlington Analytics estimates.


One bedroom: 

Two bedrooms: 

Three of more bedrooms: 

New Mid-Rise Condos:

Help Choose the number of new mid-rise condos by number of bedrooms. The number of bedrooms does not matter for APS estimates, however more bedrooms lead to more students on average in Arlington Analytics estimates.


One or two bedrooms: 

Three of more bedrooms: 

New Elevator Condos:

Help Choose the number of new elevator condos by number of bedrooms. The number of bedrooms does not matter for APS estimates, however more bedrooms lead to more students on average in Arlington Analytics estimates.


One or two bedrooms: 

Three of more bedrooms: 

New Apartments:

Help Choose the number of new apartments by type. The number of bedrooms unavailable, and does not matter for APS or Arlington Analytics estimates.


Garden: 

Mid-rise: 

Elevator: 

New Committed Affordable Housing Units:

Help Choose the number of new committed affordable residences by type. The number of bedrooms is unavailable and does not matter for APS or Arlington Analytics estimates. Arlington Analytics estimates the effects of new residences on a unit-by-unit basis; a unit is either market rate or affordable. Choosing Mixed Market residences is split evenly between committed affordable residences and market rate residences. For APS estimates, mid-rise units are not considered separately, and are split evenly among elevator and garden units.


Elevator: 

Mid-Rise: 

Garden: 

Mixed Market/CAF Elevator: 

Mixed Market/CAF Garden: 

New Elementary Students:

Estimated by Arlington Analytics



Estimated by Arlington Public Schools



The Boring Stuff: APS estimates are derived from formulas published in the Appendix (Student Generation Rates) in the 2019 Enrollment Report. Arlington Analytics estimates are derived from a dataset constructed with the following data:



Arlington Analytics estimates the county-wide relationship between residences and elementary school enrollment using a restricted, non-linear least squares estimation approach. We explicitly do not assume differences in residence effects by school. Larger units (i.e., more bedrooms) are restricted to generate at least as many students on average as smaller units. In many cases, the number of estimated students generated from larger units is indistinguishable from smaller units. This is why some options (four bedroom single-family houses, for example) are not explicitly available. Residences can only have a non-negative effect on new student enrollment. Arlington Analytics locates the planning unit for every residence in Arlington county, adds up the number of residences in each planning unit, and regresses the number of students against the number and types of residences. This approach allows us to make better predictions across a wider variety of scenarios. For example, our approach allows us to make more sensible predictions of the effects of much larger new houses relative to older, smaller houses. Additionally, it allows us to make more sensible predictions of the effects of new apartments, condos, and affordable housing units in wide areas of the county.
Not all students will go to the school to which they are assigned, students may end up attending the county's option schools. Therefore, the effect on the neighborhood school to which the new construction is designated may be smaller than predicted by either APS or Arlington Analytics. Arlington Analytics estimates are based a one-year mismatch on the data---the dataset includes 2017-2018 school year enrollment matched with January 2019 property data.