ECON 3500 Econometrics and Applications
Spring 2026
In-Class Activity: Regression Validity
Example 1: Catholic Schooling and Educational Attainment
A researcher studies whether attending a Catholic high school increases graduation and college attendance. Students who attend Catholic schools may also come from families that are more motivated, more religious, or more education-focused to begin with.
Goal: __________________________________________
Main diagnosis: __________________________________
Why?
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One fix:
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ECON 3500 Econometrics and Applications
Spring 2026
In-Class Activity: Regression Validity
Example 2: Oregon Medicaid Lottery
The Oregon Health Insurance Experiment used a lottery to study the effects of Medicaid for low-income uninsured adults in Oregon. A policymaker wants to use those estimates to predict what the effects would be in a very different state with different hospitals, demographics, and eligibility rules.
Goal: __________________________________________
Main diagnosis: __________________________________
Why?
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One fix or follow-up question:
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ECON 3500 Econometrics and Applications
Spring 2026
In-Class Activity: Regression Validity
Example 3: Survey Earnings vs. Administrative Records
Bound and Krueger compare workers' self-reported earnings in surveys to administrative earnings records. Suppose a researcher estimates the effect of earnings on some outcome using only the self-reported survey measure.
Goal: __________________________________________
Main diagnosis: __________________________________
Why?
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One fix:
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ECON 3500 Econometrics and Applications
Spring 2026
In-Class Activity: Regression Validity
Example 4: Wages of Married Women
In Heckman’s classic sample-selection setup, wages are only observed for married women who choose to work. A researcher regresses wages on education using only women with observed wages.
Goal: __________________________________________
Main diagnosis: __________________________________
Why?
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One fix:
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ECON 3500 Econometrics and Applications
Spring 2026
In-Class Activity: Regression Validity
Example 5: Children and Mothers' Labor Supply
A researcher regresses a mother’s labor supply on the number of children she has and finds that women with more children work less. He concludes that having another child reduces labor supply by exactly that amount.
Goal: __________________________________________
Main diagnosis: __________________________________
Why?
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One fix:
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ECON 3500 Econometrics and Applications
Spring 2026
In-Class Activity: Regression Validity
Example 6: Earnings and Experience
Following the classic earnings literature, a researcher regresses log earnings on years of schooling and years of labor-market experience. She includes experience only as a linear term, even though the earnings profile appears to rise early in the career and then flatten.
Goal: __________________________________________
Main diagnosis: __________________________________
Why?
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One fix:
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