College Affordability Diagnosis

Technical Information

Each geographic region in the map shows net price as a percent of income for that geographic region. Below we define each.


Net Price Data:

Net Price data come from U.S. Department of Education, Institute of Education Sciences, National Center for Education Statistics (2015). Student Financial Aid Survey. Available:

Net Price is defined by NCES as:

Average net price for full-time, first-time degree/certificate-seeking undergraduates paying the in-state or in-district tuition rate who received grant or scholarship aid from federal, state or local governments, or the institution. Other sources of grant aid are excluded. Aid received aid anytime during the full aid year is included.

Average net price is generated by subtracting the average amount of federal, state or local government, or institutional grant and scholarship aid from the total cost of attendance.  Total cost of attendance is the sum of published tuition and required fees (lower of in-district or in-state), books and supplies and the weighted average room and board and other expenses.

The weighted average for room and board and other expenses is generated as follows:

  (amount for on-campus room, board and other expenses * # of students living on-campus.
  +  amount for off-campus (with family) room, board and other expenses * # of students living off-campus with family
  +  amount for off-campus (not with family) room, board and other expenses * # of students living off-campus not with family)

divided by the total # of students.

Students whose living arrangements are unknown are excluded from the calculation.  For some institutions the # of students by living arrangement will be known, but dollar amounts will not be known.  In this case the # of students with no corresponding dollar amount will be excluded from the denominator.

Applicable to public institutions with standard calendar systems (semester, quarter, trimester, 4-1-4) that report financial aid data for students enrolled for the FALL and received aid anytime during the full aid year.

Full-time, first-time degree/certificate-seeking undergraduates - A student enrolled in a 4- or 5-year bachelor's degree program, an associate's degree program, or a vocational or technical program below the baccalaureate level, who has no prior postsecondary experience, and is enrolled for 12 or more semester credits, or 12 or more quarter credits, or 24 or more contact hours a week each term.

In-state tuition is the tuition charged by institutions to those students who meet the state's or institution's residency requirements. In-district tuition is the tuition charged by the institution to those students residing in the locality in which they attend school and may be a lower rate than in-state tuition if offered by the institution.

Source: Student Financial Aid File Dictionary,


Income Data:

Income data come from the American Community Survey, 5-year estimates, 2009-2013. Table B22008-01, “Median Household Income in the Last 12 Months,” Technical Information and Definitions available:


Shape files:

Shape files for each state come from the Census Bureau,  “Cartographic Boundary Shape files - Census Tracts.” Available:


Calculation of net prices

The net price for a given census tract is based on the distance weighted average of net prices for all institutions of a given type within the state, with the nearest institutions weighted most heavily, and furthest institutions receiving the least weight. In particular, we used Kriging via inverse log distance for every census tract, based on the locations for each institution as reported in IPEDS.

Estimation for legislative districts is based on areal estimation from census tracts within the legislative district.