How and why studies disagree about the effects of education on health: A systematic review and meta-analysis of studies of compulsory schooling laws

Abstract

Rich literatures across multiple disciplines document the association between increased educational attainment and improved health. While quasi-experimental studies have exploited variation in educational policies to more rigorously estimate the health effects of education, there remains disagreement about whether education and health are causally linked. The aim of this study was to conduct a systematic review and meta-analysis to characterize this literature, with a focus on quasi-experimental studies of compulsory schooling laws (CSLs). Articles from 1990 to 2015 were obtained through electronic searches and manual searches of reference lists. We searched for English-language studies and included manuscripts if: (1) they involved original data analysis; (2) outcomes were health-related; and (3) the primary predictor utilized variation in CSLs. We identified 89 articles in 25 countries examining over 25 health outcomes, with over 600 individual point estimates. We systematically characterized heterogeneity on key study design features and conducted a meta-analysis of studies with comparable health outcome and exposure variables. Within countries, studies differed in terms of birth cohorts included, the measurement of health outcomes within a given category, and the type of CSL variation examined. Over 90% of manuscripts included multiple analytic techniques, such as econometric and standard regression methods, with as many as 31 "primary" models in a single study. A qualitative synthesis of study findings indicated that educational attainment has an effect on the majority of health outcomes-most beneficial, some negative-while the meta-analysis demonstrated small beneficial effects for mortality, smoking, and obesity. Future work could focus on inconsistent findings identified by this study, or review the health effects of other types of educational policies.

Longer schooling but not better off? A quasi-experimental study of the effect of compulsory schooling on biomarkers in France

“…An extensive literature in economics and public health has used these reforms to examine the causal effect of schooling duration on a range of adult specific diseases and risk factors (Banks & Mazzona, 2012;Davies, Dickson, Davey Smith, van den Berg, & Windmeijer, 2018;Dursun & Cesur, 2016;Glymour, Kawachi, Jencks, & Berkman, 2008;Huang, 2015;Nafilyan, Avendano, & De Coulon, 2017;Nguyen et al, 2016;Schneeweis, Skirbekk, & Winter-Ebmer, 2014), health behaviors (Jurges, Reinhold, & Salm, 2011;Silles, 2015), health-related knowledge (Johnston, Lordan, Shields, & Suziedelyte, 2015), and mortality (Albouy & Lequien, 2009;Clark & Royer, 2013;Gathmann, Jurges, & Reinhold, 2015;Lager & Torssander, 2012;Lleras-Muney, 2005). However, a recent review and metaanalysis of the health effects of compulsory schooling laws identified a paucity of research on biomarkers of health (Hamad, Elser, Tran, Rehkopf, & Goodman, 2018). Indeed, only three studies to date have focused on biomarkers; and their findings offer contradictory evidence of a causal relationship.…”

“…reform on 16 biological indicators of sub-clinical disease including anthropometrics, blood glucose, lipids, blood pressure, as well as liver and kidney function. This large array of biomarkers enables us to consider different health dimensions, as previous research has showed that compulsory schooling laws can improve some outcomes while negatively affecting others (Hamad et al, 2018). We use data from a unique population-based survey that collected both educational attainment data and extensive health and biological measures in nearly 60,000 adults living in France at the time of the study.…”

Using Cross-Cultural Studies to Improve Evidence on Dementia Prevention: Lessons from the Special Issue Sponsored by the International Research Network on Dementia Prevention (IRNDP)

“…The major limitations in these studies is the difficulty of ruling out the confounding influence of individual characteristics such as intelligence or childhood socioeconomic status that may influence both schooling and late-life cognition. Evidence from studies in settings with very different confounders [5], or based on natural experiments that could not plausibly be influenced by individual characteristics [6], strengthens the overall evidence base, even if the new studies have different limitations.…”

Can Social Policies Improve Health? A Systematic Review and Meta‐Analysis of 38 Randomized Trials

“…This tendency to publish only positive findings might explain why the extant quasi‐experimental literature shows that social policies produce a greater health benefit than we found in our review. For example, Hamad and colleague's meta‐analysis of quasi‐experimental evaluations of law‐mandated increases in schooling duration found that these policies were associated with decreased probability of obesity (effect size: −0.20; 95% CI −0.40 to −0.02) 112 . In our review, which included different interventions than those evaluated by Hamad and coauthors, experiments in the early life and education domain were not associated with lower obesity risk 49,52 …”