A012025 starting populationThe simulation starts with South Africa in 2025: 63.1 million people, of whom 6.6 million are aged 60 or older. Ageing is moved forward one year at a time to 2100.
The Politics of an Ageing Electorate
How voter age structure can redirect spending and intergenerational transfers.
PDF · 15 pages · 0.93 MB · 02.04 · GSX:POP-004
Study record · GSX:POP-004
How can voter age structure redirect spending and intergenerational transfers?
Evidence status: Modelled. Exploratory simulation. Version 1.0. Peer review: none. The paragraph under the title is the published summary.
Conditional answer · GSX:POP-004:C01
In the 2025 calibration, people aged 60 or older are 15.1 percent of adults but 20.7 percent of votes cast. Applying the 2024 age-turnout pattern produces a median voter aged 43, four years older than the median adult.
Evidence status: Modelled. Sensitivity: moderate. Depends on GSX:POP-004:A01, GSX:POP-004:A02, GSX:POP-004:A03. The turnout rates are a strong pattern extrapolated from identification scans, not a perfect census of every voter. The median voter is the age that splits votes cast in half. It is not one person whose wishes become policy.
C01
Related questions
- How does an ageing electorate change the politics of public spending?
- What happens to intergenerational transfers when the median voter is older?
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Assumptions
Assumptions
These are the registered model assumptions. A result stays conditional on the ones a claim names.
A022024 age-turnout patternVotes are estimated by applying the Electoral Commission's 2024 age-turnout pattern. Those rates come from identification scans for 9.17 million of 16.29 million voters who voted, then extrapolated.qualitative not a scalar
A03Age-60 boundaryOlder adult means a person aged 60 or older, the current old-age grant age and the series benchmark. It does not mean every such person has retired or shares one preference.60 years
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Model
Model
The registered model statement. It is a scenario model, and the manuscript remains the full specification.
M01Electorate-versus-population cohortA simple cohort model moves the 2025 age structure to 2100 under three fertility, longevity, and migration paths, then applies fixed or feedback turnout. It is built to expose relationships. It is not an official population forecast.GSX:POP-004:M01
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Results
Results
Modelled scenario results. They are not forecasts.
R0120.7 percent of votes cast by people aged 60 or olderIn the 2025 calibration, people aged 60 or older are 15.1 percent of adults and 20.7 percent of votes cast. The median voter is 43, four years older than the median adult.2025 calibration with the 2024 age-turnout pattern
R0246.0 percent of votes in 2100, baseline ageing, fixed turnoutUnder baseline ageing, the age-60-plus bloc overtakes voters aged 18 to 34 around 2039 and supplies 46.0 percent of votes by 2100 with fixed turnout. The median voter is 57, still below retirement age. Accelerated ageing produces a median voter of 60 in 2085, or 2081 with turnout feedback.Baseline and accelerated scenarios to 2100
Sensitivity
- High · 1
- Moderate · 1
- Low · 0
Limitations
The turnout rates are a strong pattern extrapolated from identification scans, not a perfect census of every voter. The median voter is the age that splits votes cast in half. It is not one person whose wishes become policy.
The paths are deliberately simple cohort mechanics, not an official forecast. Accelerated ageing is a severe stress test. Mobilisation can still change the electorate even when the population cannot change quickly.
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Claims
Claims
Each claim names the assumptions it uses and the limitation that travels with it.
C01GSX:POP-004:C01In the 2025 calibration, people aged 60 or older are 15.1 percent of adults but 20.7 percent of votes cast. Applying the 2024 age-turnout pattern produces a median voter aged 43, four years older than the median adult.Modelled · moderate sensitivity
C02GSX:POP-004:C02Under the baseline path, voters aged 60 or older overtake voters aged 18 to 34 around 2039 and cast 46.0 percent of votes by 2100 if age-specific turnout stays fixed. The median voter remains below retirement age. Only the accelerated-ageing scenario produces a retired median voter within the century, in 2085 with fixed turnout and in 2081 with feedback.Modelled · high sensitivity
Sources and reproducibility
The PDF and complete Markdown source are both published.
Full manuscript: 3 869 words across 15 indexed headings. Source checksum: 538d7baae4fb…. Code recorded: yes. Data recorded: yes. Environment recorded: no. Published files: 3. the published statement does not rely on a recorded random seed A public code repository is not published.
Community record · version 1.0
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Pakang Senosha is the author on this version. External review: none. A later critique or revision appears here after a person publishes it.
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greyscienx.com/research/population-futures/the-politics-of-an-ageing-electorate
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