Middle Years Development Instrument (MDI) Child Well-Being and Assets in a Predominantly Hispanic/Latinx Student Population

Abstract Monitoring child development at the population level is essential for informing research, policy, and practice. There is limited population-level data on middle childhood (ages 10–13)—a critical developmental stage marked by biological, cognitive, and socioemotional changes—as well as a lack of self-report data from Hispanic/Latinx children. This U.S.-based study aimed to (1) describe 5th and 6th grade students’ self-reported Middle Years Development Instrument (MDI) scores on optimism, happiness, self-esteem, sadness, and general health (i.e., MDI well-being components) and adult support, health behaviors, peer relationships, school experiences, and activity engagement (i.e., MDI developmental assets); (2) examine correlations between MDI well-being components and assets; and (3) identify potential developmental differences in MDI scores between 5th and 6th graders. Using cross-sectional MDI data, we analyzed responses from 757 students in two predominantly Hispanic/Latinx (81.9%) Los Angeles County school districts, collecting data from 5th graders in 2019 and 6th graders in 2023. Ordinal logistic regression analyses revealed that adult, health, peer, and school MDI assets were significantly correlated with higher odds of MDI well-being components, with small to large effect sizes. Notably, adult and health MDI assets had protective benefits for 6th graders, partially offsetting their generally lower MDI well-being; in contrast, the MDI activity asset was not significantly correlated with outcomes in any MDI well-being component. Findings highlight the utility of the MDI in understanding associations between specific developmental assets and components of well-being during middle childhood. Developmental transitions may strengthen or attenuate the protective effects of assets.