SCHEV's Return on Investment (ROI) Model relates four estimates to compare the cost of a given degree program with its expected return. First, the model compares an estimate of lifetime earnings for holders of that college degree to an estimate of the average expected earnings for holders of a high school diploma. Then the model scales that result with the cost of that degree, which is defined as the sum of student loans and net price. How those values are calculated appears below.
The model starts with constructing a lifetime wage projection model using person-level wage data spanning 25 years, via these five steps:
- Adjust for inflation: Wage data of graduates from 1995-96 to 2019-20 are adjusted to 2023 values, by each year post-completion for which wages are available, for at least three quarters of the calendar year.
- Smooth for year-to-year noise: To minimize the impact of random and short-term fluctuations, seven-year moving averages are calculated using median wages per program level and "program area" of instructional program (i.e., two-digit CIP code).
- Model starting wage and growth: A linear regression model is constructed for each program area at each program level based on historic performance of wages from 1995-96 to 2019-20. For each program level, we limit records to only graduates whose highest degree earned is at the same level.
- Constrain population: Graduates who have earned both Bachelor’s and Master’s degrees are not included in the construction of the model for Bachelor’s level wage projection.
- Extrapolate: The model assumes wage changes follow the same pattern beyond 2019-20 in each program area and at each program level and then project a lifetime wage income for graduates individually, using their fourth-year postgraduation wages as an anchor.
Estimating lifetime earnings: Using the 2018-19 Bachelor’s graduating cohort as the study population: Individuals with valid wage data in 2023, and no higher level of degree, are included in the analysis. Assuming these individuals continue to work until age 67 when they reach full retirement under Social Security, the regression model is applied on a by-graduate basis, and their lifetime wage income from 2020 is calculated, until the year they turn 67. In other words, individuals have varying numbers of working years based on their age at graduation, which in turn is based on age at entry and the time spent completing their degree. The longer a student stays in school, typically the lower their lifetime earnings.
Comparison to no college: In parallel, the model constructs a counterfactual lifetime wage projection for the same population where the individuals never entered college, via these three steps:
- Adjust for inflation: Census Bureau’s ACS 5-year estimates of wages for high school (HS) graduates in Virginia from 2010 to 2023 are adjusted to 2023 values.
- Estimate start and growth: Linear regression coefficients are calculated based on the above ACS estimates. HS level wages beyond 2023 are projected based on the historic pattern of change in the past 14 years.
- Extrapolate: Assuming each individual included in the analysis would enter the workforce upon HS graduation, earning HS level wage each year up to age 67, we calculate their HS lifetime wage income. This eliminates the opportunity cost of time in college.
Cost of college: The total cost of a Bachelor’s degree is calculated for each student as the sum of total student loans and net price charged to each student (i.e., institutional budget minus all gift aid in each semester enrolled in a Bachelor’s program). Net prices are adjusted to 2023 equivalents.
- The projected Bachelor’s lifetime wage represents the total gain from earning a Bachelor’s degree.
- The sum of projected high school graduate-level lifetime wages represents the counterfactual comparison.
- The total cost of earning a Bachelor’s degree and years delayed entering the workforce full-time combined represent the real and opportunity costs of earning a Bachelor’s degree.
Contrast gain with loss: The model then contrasts the total gain and total loss. The ROI estimates are represented in two different calculations:
- Net Lifetime Difference=[Projected Bachelor’s Lifetime Wages]-[Projected HS Lifetime Wages]-[ Student Debt]-[Net Price]
- This is the estimated difference in dollars between college and no college (for this program), subtracting the cost of college.
- ROI ratio=[Projected Bachelor’s Lifetime Wages]/([Projected HS Lifetime Wage]+[Student Debt]+[Net Price])
- This is the estimated lifetime wages, but divided by or scaled by the comparison of projected HS lifetime wages and college costs.
A positive Net Lifetime Difference shows a net gain from earning a Bachelor’s degree, the same as an ROI ratio greater than one.