The National Institute of Population and Social Security Research presents innovative methodology for reconstructing population by birth year using vital statistics, analyzing demographic structural changes.
Key Points
1. Development of Dynamic Accumulation Methodology
- Reconstructs birth year-specific populations by accumulating births and subtracting deaths from vital statistics
- Enables detailed analysis without depending on census data or resident registration
- Validates accuracy through comparison with official statistics, confirming high reliability
- Provides new analytical tool for understanding long-term demographic dynamics
2. Structural Analysis of Japan's Demographic Transition
- Population peak of 128.06 million in 2008 followed by continuous decline
- Baby boom generation (1947-1949) totaling 8.06 million births creating demographic bulge
- Second baby boom (1971-1974) with 8.16 million births showing echo effect
- Post-1975 continuous decline in births accelerating population aging
3. Birth Cohort Survival Analysis
- 1947 birth cohort: 2.68 million births, 1.89 million surviving to 2020 (70.5% survival rate)
- Significant gender differences in survival rates, with women showing higher longevity
- Regional variations in survival patterns reflecting migration and mortality differences
- Cohort effects visible in health outcomes and mortality patterns
4. Future Population Projection Implications
- Working-age population (15-64) declining from 87.16 million (1995) to 74.06 million (2020)
- Elderly population (65+) increasing from 18.26 million (1995) to 36.19 million (2020)
- Dependency ratio rising from 0.37 to 0.69, indicating increased social security burden
- Regional depopulation accelerating with youth concentration in metropolitan areas
5. Methodological Contributions and Applications
- Enables precise tracking of generational changes in population dynamics
- Facilitates policy evaluation by linking demographic events to specific cohorts
- Supports regional population analysis and projection modeling
- Provides foundation for social security system sustainability assessments
The article concludes that dynamic accumulation methodology offers powerful analytical framework for understanding Japan's demographic challenges, essential for evidence-based policy formulation addressing population decline and rapid aging.