revealed gender gaps in mathematics achievement and teacher perceptions. However, recent evidence suggests that gender gaps have closed on state tests, raising the question of whether such gaps are absent in the ECLS-K:2011 cohort. Extending earlier analyses, this study compares the two ECLS-K cohorts, exploring gaps throughout the achievement distribution and examining whether learning behaviors might differentially explain gaps more at the bottom than the top of the distribution. Overall, this study reveals remarkable consistency across both ECLS-K cohorts, with the gender gap developing early among high achievers and spreading quickly throughout the distribution. Teachers consistently rate girls' mathematical proficiency lower than that of boys with similar achievement and learning behaviors. Gender differences in learning approaches appear to be fairly consistent across the achievement distribution, but girls' more studious approaches appear to have more payoff at the bottom of the distribution than at the top. Questions remain regarding why boys outperform girls at the top of the distribution, and several hypotheses are discussed. Overall, the persistent ECLS-K patterns make clear that girls' early mathematics learning experiences merit further attention.

Objectives. To determine how sensitive estimates of lesbian, gay, bisexual, or questioning (LGBQ)–heterosexual youth health disparities are to the presence of potentially mischievous responders. Methods. We used US data from the 2015 Youth Risk Behavior Survey, pooled across jurisdictions that included a question about sexual identity for a total sample of 148 960 students. We used boosted regressions (a machine-learning technique) to identify unusual patterns of responses to 7 screener items presumably unrelated to LGBQ identification, which generated an index of suspected mischievousness. We estimated LGBQ–heterosexual youth disparities on 20 health outcomes; then we removed 1% of suspected mischievous responders at a time and re-estimated disparities to assess the robustness of original estimates. Results. Accounting for suspected mischievousness reduced estimates of the average LGBQ–heterosexual youth health disparity by up to 46% for boys and 23% for girls; however, screening did not affect all outcomes equally. Drug- and alcohol-related disparities were most affected, particularly among boys, but bullying and suicidal ideation were unaffected. Conclusions. Including screener items in public health data sets and performing rigorous sensitivity analyses can support the validity of youth health estimates.

Does achievement matter differently for men and women?

Women are underrepresented in many science, technology, engineering, and mathematics (STEM) majors and in some non-STEM majors (e.g., philosophy). Combining newly gathered data on students’ perceptions of college major traits with data from the Education Longitudinal Study of 2002 (ELS:2002), we find that perceived gender bias against women emerges as the dominant predictor of the gender balance in college majors. The perception of the major being math or science oriented is less important. We replicate these findings using a separate sample to measure college major traits. Results suggest the need to incorporate major-level traits in research on gender gaps in college major choices and the need to recognize the impact of perceptions of potential gender discrimination on college major choices.