Overview
This series explains why a short American Community Survey cross-section can make a changing college-major premium look like career decline. It moves from the age–cohort problem to the matched ACS–LEHD design, nested panel and worker-fixed-effects estimates, and the business case for separating annual earnings from labor supply and graduate education. Across robustness checks, later technical cohorts have higher premiums, while long linked histories do not show slower relative technical earnings growth in the main specifications. The evidence challenges a universal skill-decay reading, but it does not identify occupation-level obsolescence, a causal major return, or an individual career forecast.
Learning outcomes
- A downward cross-sectional technical-major profile is not by itself evidence of faster within-career skill decay.
- Cohort-specific starting premiums can be mistaken for age slopes when newer cohorts appear at younger ages.
- Linked LEHD histories and worker fixed effects make technical relative growth near zero or positive in the studied specifications.
- Annual earnings bundle wages, work attachment, and education pathways, so the evidence is relative rather than an individual forecast.
Keywords
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PlansFAQ
Why can an age–earnings curve misrepresent career growth?
It can compare different birth cohorts at different ages, so a changing starting premium may look like within-career decline.
What changes when researchers follow the same workers?
Following linked workers adds earnings histories and reduces reliance on short cross-sectional age comparisons; worker fixed effects also absorb persistent earnings differences.
Why are annual earnings not the same as wage growth?
Annual earnings combine pay with quarters worked and other labor-supply patterns, so a profile can change without matching hourly wage changes.
What does the evidence show about engineering and computer science earnings?
In the paper’s main linked specifications, engineering and computer science do not show slower relative earnings growth than the broad other-major group. This does not establish that occupation-specific skill obsolescence never occurs.