A safe and effective vaccine for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may be required to end the coronavirus disease 2019 (COVID-19) pandemic 1 – 8 . For global deployment and pandemic control, a vaccine that requires only a single immunization would be optimal. Here we show the immunogenicity and protective efficacy of a single dose of adenovirus serotype 26 (Ad26) vector-based vaccines expressing the SARS-CoV-2 spike (S) protein in nonhuman primates. 52 rhesus macaques were immunized with Ad26 vectors encoding S variants or sham control and were challenged with SARS-CoV-2 by the intranasal and intratracheal routes 9 , 10 . The optimal Ad26 vaccine induced robust neutralizing antibody responses and provided complete or near-complete protection in bronchoalveolar lavage and nasal swabs following SARS-CoV-2 challenge. Vaccine-elicited neutralizing antibody titers correlated with protective efficacy, suggesting an immune correlate of protection. These data demonstrate robust single-shot vaccine protection against SARS-CoV-2 in nonhuman primates. The optimal Ad26 vector-based vaccine for SARS-CoV-2, termed Ad26.COV2.S, is currently being evaluated in clinical trials.

Although grade retention may be consequential for a number of important educational and socioeconomic outcomes, we know surprisingly little about the actual rate at which students are made to repeat grades. We build on Hauser, Frederick, and Andrew’s (2007) measure of grade retention using data from the 1995 through 2010 Current Population Surveys. We make technical improvements to their measure; provide more recent estimates; and validate the measure against external criteria. Our measure describes large disparities in grade retention rates by sex, race/ethnicity, geographic locale, and students’ socioeconomic circumstances. However, both absolute retention rates and disparities in retention rates have declined markedly since 2005. We conclude by describing how our measures might be used to model the impact of economic and policy contexts on grade retention rates.

Following the enactment of Equal Pay legislation, there have been numerous studies conducted to determine whether comparable men and women in academe are paid differently (for a review of the literature, see Ransom and Megdal [1993]). In one way or another, all salary-equity studies seek to measure the average pay difference between two groups of workers that would exist after taking into account the differences in their qualifications that should affect pay. We refer to this difference as the average unexplained wage gap, which is often interpreted as being a measure of pay discrimination. Accordingly, salary equity is said to be achieved when the average unexplained wage gap is zero. The average unexplained wage gap is found by calculating the difference in average salaries between the two groups (average wage gap), and then subtracting from this difference the portion that is due to differences in the average qualifications of workers (average explained wage gap). In addition, many studies also calculate the unexplained wage gaps for individuals within each group.When conducting a salary-equity study, considerable time and effort are devoted to issues such as deciding who should be included in the analysis, whether to represent salary by dollars or logarithms of dollars, and what factors to control for in the salary model. As Ferber and Loeb discuss in Chapter Two, researchers often disagree as to whether it is proper to control for factors such as academic rank, and the average unexplained wage gap can vary greatly depending on the salary model specification.Once these issues have been resolved, it is tempting to conclude that all of the difficult decisions have been made and that once the salary model

It is an activity of the W. E. Upjohn Unemployment Trustee Corporation, which was formed in 1932 to administer a fund set aside by the late Dr W. E. Upjohn for the purpose of carrying on "research into the causes and effects of unemployment and measures for the alleviation of unemployment." The facts presented in this study and the observations and viewpoints expressed are the sole responsibility of the authors. They do not necessarily represent positions of the W. E. Upjohn Institute for Employment Research.

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