Teacher shortages in mathematics and science are widely recognized as a global challenge, yet systematic evidence on their long-term evolution and unequal distribution across schools remains limited. Existing research has often relied on single-country studies, short time horizons, or aggregate indicators that obscure within-system inequalities (Darling-Hammond & Sykes, 2003; Sutcher et al., 2019). As a result, less is known about whether shortages persist over time and whether they disproportionately affect specific types of schools. This study addresses these gaps by providing a longitudinal, cross-national analysis of STEM teacher shortages using four cycles of the Trends in International Mathematics and Science Study (TIMSS 2011, 2015, 2019, and 2023). Drawing on principals’ reports from more than 40 education systems at Grade 4 and more than 30 systems at Grade 8, we examine trends in shortages of teachers specialized in mathematics and science over a twelve-year period. To ensure comparability over time, analyses are restricted to education systems participating in all four TIMSS cycles. Moving beyond national averages, teacher shortages are conceptualized as a distributional phenomenon, and their prevalence is examined by school socioeconomic status (SES) and urbanicity. Pooled, school-weighted shortage rates are estimated separately by grade, subject, cycle, and school context, consistent with distributional perspectives emphasizing that staffing constraints may cluster in disadvantaged settings (García & Weiss, 2020). Results reveal three central findings. First, mathematics and science teacher shortages are persistently widespread across education systems, affecting a majority of schools in every cycle. At Grade 4, science shortages consistently exceed mathematics shortages, highlighting particular vulnerabilities in primary-level science staffing. At Grade 8, shortages display greater temporal volatility, especially in science, with evidence of partial decline by 2023. Second, shortages are strongly and persistently stratified by socioeconomic status. Schools serving socioeconomically disadvantaged student populations report shortage rates that are typically 10–20 percentage points higher than those of more advantaged schools, with gaps remaining stable or widening over time, aligning with evidence that staffing challenges are more severe in disadvantaged communities (Sutcher et al., 2019). Third, urban–rural differences are comparatively smaller and less systematic, particularly at Grade 4, although rural disadvantages are more consistently observed at Grade 8. These findings demonstrate that STEM teacher shortages are not merely a temporary labor-market imbalance but a durable form of educational inequality. This study reframes teacher shortages as an equity issue with direct implications for opportunity structures and targeted workforce policy (Darling-Hammond & Sykes, 2003).

Darling-Hammond, L., & Sykes, G. (2003). Wanted: A national teacher supply policy for education—The right way to meet the “highly qualified teacher” challenge. Education Policy Analysis Archives, 11(33), 1–57. https://doi.org/10.14507/epaa.v11n33.2003 García, E., & Weiss, E. (2020). Examining the factors that play a role in the teacher shortage crisis. Economic Policy Institute. Sutcher, L., Darling-Hammond, L., & Carver-Thomas, D. (2019). Understanding teacher shortages: An analysis of teacher supply and demand in the United States. Education Policy Analysis Archives, 27(35). https://doi.org/10.14507/epaa.27.3696