Age–Sex Structural Dissimilarity Between Saudi and Non-Saudi Populations in Saudi Arabia, 2010–2024: Decomposition, Cohort Change, and Indicators for Population Planning

Saudi Arabia’s citizen population is undergoing demographic transition, while its large non-Saudi population is shaped by international migration. Using official GASTAT estimates for 2010–2024, this study quantifies Saudi–non-Saudi age–sex structural dissimilarity with Duncan’s index, cell-level and counterfactual decompositions, year-on-year distances, and cohort-change ratios. Joint dissimilarity rose from 36.61 to 44.28, mostly in 2010–2015 (+6.72 points), the years most affected by back-casting, and changed little thereafter (+0.95 after 2015). Changes in the non-Saudi structure widened the gap in 2010–2024 (+9.79 points) and 2015–2024 (+3.09), whereas Saudi demographic change narrowed it (−2.11 and −2.14). The non-Saudi structure moved more than the Saudi structure every year, but much of this movement reversed; its structural distance between 2015 and 2024 was about 1.4 times the Saudi distance. The largest male contribution shifted from ages 30–34 in 2015 to 35–39 in 2024. Cohort-change ratios for 2015–2024 indicate net losses at older working ages and renewed net gains of young men after 2019, whereas ratios for 2010–2015 partly reflect distortions in the early back-cast estimates. The total dependency ratio for all residents (33.8 in 2024) was 25.8 points below the Saudi ratio (59.6), so pooled national indicators understate the dependency burden of the citizen population.