Cory Koedel

We study the incidence of Social Security taxes on teacher wages and employment. On average, we estimate teachers with Social Security coverage take home 9.6 percent less in wages than observationally similar teachers in similar districts without Social Security coverage. This accounts for about three-fourths of the 12.4-percent total Social Security tax. Moreover, our analysis suggests this is likely a lower-bound estimate of the true incidence of Social Security taxes – under reasonable assumptions, we cannot rule out full (100%) tax incidence on teacher wages. We find no evidence of tax incidence on teacher staffing levels.

During the 2015–2016 academic year, racial protests swept across college campuses in the U.S. These protests were followed by large university investments in initiatives to promote diversity, which combined with existing diversity dynamics, have helped to shape recent faculty diversity trends. We document diversity trends among faculty in STEM and non-STEM fields since the protests in 2015–2016. We find that recent diversity trends are narrowing the gender gap among faculty in STEM and non-STEM fields, but widening racial-ethnic gaps, especially among Black faculty. A large body of prior research suggests these trends will affect students’ college experiences and how they choose majors.

We estimate the education and earnings returns to enrolling in technical 2‐year degree programs at community colleges in Missouri. A unique feature of the Missouri context is the presence of a highly regarded, nationally ranked technical college: State Technical College of Missouri (State Tech). We find that enrolling in a technical program in Missouri increases the likelihood of associate degree attainment and post‐enrollment earnings, but that the positive effects statewide are driven largely by students who attend State Tech. These findings demonstrate the potential for a high‐performing community college to change students' education and labor market trajectories. At the same time, they exemplify the potential for substantial institutional heterogeneity in the returns to postsecondary education.

We study the effects of exposure to nonresident students on the outcomes of undergraduate in‐state students during a period of high nonresident enrollment growth at the University of Missouri‐Columbia. Our models leverage within‐major, cross‐time variation in nonresident exposure for identification. We find no evidence that increased exposure to domestic nonresidents affects in‐state student outcomes and our null results are precisely estimated. We find evidence of modest negative impacts on in‐state students when their exposure to foreign students increases using our preferred specification. However, the identifying variation in exposure to foreign students in our data is limited and this result is not robust in all of our models. (JEL I23, I28, R23)

We examine pension-cost crowd out of salary expenditures in the public sector using a 15-year data panel of state teacher pension plans spanning the Great Recession. While there is no evidence of salary crowd out prior to the Great Recession, there is a shift in the post-recession years such that a 1% (of salaries) increase in the annual required pension contribution corresponds to a decrease in total teacher salary expenditures of 0.24%. The effect operates through changes to the size of the teaching workforce, not changes to teacher wages. An explanation for the effect heterogeneity pre- and post-recession is that public employers are less able to shield the workforce from pension costs during times of fiscal stress. This problem is exacerbated because unlike other benefit costs, such as for health care, pension costs are countercyclical.

Like other public workers, teachers typically receive high and compressed ratings that do little to differentiate them based on performance. Motivated by empirical evidence of substantial variation in effectiveness among teachers, there has been a recent push to develop more informative evaluation systems with greater ratings dispersion. We study one of the first of these new systems, implemented in Tennessee, in order to understand how teachers respond to the provision of new, more differentiated performance ratings. We focus on whether summative ratings influence teachers’ self-reported, self-directed professional improvement activities as measured by four items on a statewide teacher survey. Using a regression discontinuity design we find no evidence that teachers alter their time investments in professional improvement, or adjust their professional improvement activities based on evaluation feedback, in response to their ratings.

We study the relative performance of two policy-relevant value-added models—a one-step fixed effect model and a two-step aggregated residuals model—using a simulated data set well grounded in the value-added literature. A key feature of our data generating process is that student achievement depends on a continuous measure of economic disadvantage. This is a realistic condition that has implications for model performance because researchers typically have access to only a noisy, binary measure of disadvantage. We find that one- and two-step value-added models perform similarly across a wide range of student and teacher sorting conditions, with the two-step model modestly outperforming the one-step model in conditions that best match observed sorting in real data. A reason for the generally superior performance of the two-step model is that it better handles the use of an error-prone, dichotomous proxy for student disadvantage.