# Research: Indices and Measures of Intergenerational Wealth/Income Transmission ## Identification The user is most likely thinking of one (or a combination) of the following: 1. **The Intergenerational Earnings Elasticity (IGE)** — the single most canonical measure of how much income is "passed down" across generations. It is the coefficient β in ln(child income) = α + β × ln(parent income). A higher β means more persistence (less mobility). This is the measure used by Corak (2013), the OECD (2018), the World Bank (2018, 2025), and in South Africa by Piraino (2015) and Finn et al. (2016). It is what underpins the famous "Great Gatsby Curve." 2. **The WEF Global Social Mobility Index (2020)** — a composite index ranking 82 countries on 10 pillars. South Africa ranked 77th. This is the most likely "named index" the user recalls. 3. **The OECD "generations to reach mean income" metric** from *A Broken Social Elevator?* (2018) — which estimated it would take **9 generations** for a low-income South African family to reach the average income (tied with Brazil, second-worst of 30 countries). 4. **The rank-rank slope** (Chetty et al. 2014) — the correlation between parent and child income percentile ranks, increasingly preferred over IGE because it is less sensitive to extreme values. There is no single "Intergenerational Wealth Index" by that name. The closest named indices are the WEF Global Social Mobility Index and the World Bank's Global Database on Intergenerational Mobility (GDIM). The academic literature uses IGE and rank-rank slopes as the standard quantitative measures. ## Summary There is no single canonical "wealth mobility index" — rather, a family of measures quantifying how much economic status is transmitted across generations. The intergenerational earnings elasticity (IGE) is the foundational metric; the WEF Global Social Mobility Index is the most prominent composite index. For South Africa, the evidence is stark: the IGE ranges from 0.57 to 0.83 depending on methodology, the WEF ranked South Africa 77th of 82 countries, and the OECD estimated 9 generations for a poor family to reach mean income — among the worst in the world. --- ## Findings ### World Bank — Fair Progress? Economic Mobility Across Generations Around the World (GDIM) - **Source:** World Bank (Narayan, van der Weide et al.) - **URL:** https://www.worldbank.org/en/topic/poverty/publication/fair-progress-economic-mobility-across-generations-around-the-world - **Published:** 2018-05-09 - **Validity:** Official statistics - **Summary:** The World Bank's landmark report introducing the Global Database on Intergenerational Mobility (GDIM), covering 148 economies and birth cohorts 1940–1989 with 96% world population coverage. It measures both absolute mobility (share of children with more education than parents) and relative mobility (dependence of child's schooling on parents' schooling). Africa and South Asia have the lowest mobility globally. - **Key data points (time-referenced):** - 2018: GDIM covers 148 economies, birth cohorts 1940–1989, 96% of world population - 2018: In some low-income African countries, only 12% of young adults born in the 1980s have more education than their parents - 2018: The developing world accounts for 46 of the bottom 50 economies in education mobility from bottom to top ### World Bank — Global Database on Intergenerational Income Mobility (2025) - **Source:** World Bank (Munoz & van der Weide, Policy Research Working Paper 11166) - **URL:** https://documents1.worldbank.org/curated/en/099149507072519419/pdf/IDU-a6244ff6-f76f-41cb-8e51-f84b5491b362.pdf - **Published:** 2025-07 - **Validity:** Official statistics - **Summary:** A new global database with IGE estimates for 87 countries covering 84% of the world's population, using the Two-Sample Two-Stage Least Squares (TSTSLS) approach with retrospective parental education/occupation data from 156+ surveys. Confirms the Great Gatsby Curve (negative association between mobility and inequality) holds across this wider set of countries, including 44 developing countries. Income mobility is lower in the developing world on average. - **Key data points (time-referenced):** - 2025: IGE ranges from 0.14 (Sweden, lowest) to 0.96 (Madagascar, highest) across 87 countries - 2025: Database covers 87 countries, 84% of world population, individuals born in the 1980s–1990s ### OECD — A Broken Social Elevator? How to Promote Social Mobility - **Source:** OECD - **URL:** https://www.oecd.org/content/dam/oecd/en/publications/reports/2018/06/a-broken-social-elevator-how-to-promote-social-mobility_g1g8e196/9789264301085-en.pdf - **Published:** 2018-06-15 - **Validity:** Official statistics - **Summary:** The OECD's comprehensive report on social mobility across OECD and selected emerging economies. It introduces the "generations to reach mean income" metric — how many generations it takes for children born into the bottom 10% to reach the average income. On average across OECD countries it takes 4–5 generations; Nordic countries need only 2–3. South Africa is tied with Brazil at 9 generations, second-worst after Colombia (11 generations) among 30 countries assessed. - **Key data points (time-referenced):** - 2018: South Africa and Brazil tied at 9 generations for low-income family offspring to reach average income (2nd-worst of 30 countries; only Colombia worse at 11) - 2018: OECD average is 4–5 generations; Denmark, Norway, Finland, Sweden need only 2–3 generations - 2018: Report covers 30 countries with IGE-based intergenerational earnings persistence estimates ### WEF — Global Social Mobility Index 2020 - **Source:** World Economic Forum - **URL:** https://en.wikipedia.org/wiki/Global_Social_Mobility_Index (summary of WEF report at https://www3.weforum.org/docs/Global_Social_Mobility_Report.pdf) - **Published:** 2020-01-19 - **Validity:** Institutional report - **Summary:** The WEF's inaugural (and only) Global Social Mobility Index, ranking 82 countries across 10 pillars spanning 5 determinants: health, education, technology, work, and institutions. Unlike IGE-based measures, it measures the *causes* of mobility rather than mobility outcomes. Denmark ranked first (85.2); South Africa ranked 77th of 82 (41.4), ahead of only Bangladesh, Pakistan, Cameroon, Senegal, and Ivory Coast. The index has not been updated since 2020. - **Key data points (time-referenced):** - 2020: South Africa ranked 77th of 82 countries, index score 41.4 - 2020: Denmark ranked 1st with score 85.2; United States 27th (70.4); China 45th (61.5); India 76th (42.7) - 2020: A 10% increase in social mobility would boost economic growth, per WEF analysis ### Corak (2013) — The Great Gatsby Curve: Intergenerational Earnings Elasticity by Country - **Source:** Miles Corak, Journal of Economic Perspectives, 27(3): 79–102 - **URL:** http://piketty.pse.ens.fr/files/Corak2013.pdf - **Published:** 2013-07 (Summer 2013) - **Validity:** Peer-reviewed study - **Summary:** The seminal paper establishing the "Great Gatsby Curve" — the negative cross-country relationship between income inequality and intergenerational mobility. Provides methodologically adjusted IGE estimates for 22 countries. In Nordic countries (Denmark, Norway, Finland), less than one-fifth of a father's economic advantage is passed to a son. In Italy, the UK, and the US, roughly 50% of advantage is transmitted. Lower-income countries occupy even higher positions on the curve. - **Key data points (time-referenced):** - 2013: IGE estimates for 22 countries; Nordic countries <0.20; US and UK ~0.50; Italy ~0.50 - 2013: Cohorts born early-to-mid 1960s, adult outcomes measured mid-to-late 1990s - 2013: Negative correlation between Gini coefficient (circa 1985) and intergenerational earnings elasticity ### Charles & Hurst (2003) — The Correlation of Wealth Across Generations - **Source:** Kerwin Kofi Charles & Erik Hurst, Journal of Political Economy, 111(6) - **URL:** https://erikhurst.com/wp-content/uploads/2020/02/charles_hurst_wealth_jpe.pdf - **Published:** 2003-12 - **Validity:** Peer-reviewed study - **Summary:** The foundational study of intergenerational *wealth* (not income) persistence. Finds an age-adjusted elasticity of child wealth with respect to parental wealth of 0.37 before the transfer of bequests. Lifetime income and asset ownership jointly explain nearly two-thirds of the wealth elasticity; education, past parental transfers, and expected future bequests account for little of the remainder. Suggests children's savings propensities are learned from parents. - **Key data points (time-referenced):** - 2003: Age-adjusted intergenerational wealth elasticity = 0.37 (before bequests transfer) - 2003: Lifetime income and asset ownership explain ~2/3 of the wealth elasticity ### Chetty et al. (2014) — Rank-Rank Intergenerational Mobility in the United States - **Source:** Raj Chetty, Nathaniel Hendren, Patrick Kline, Emmanuel Saez, Nicholas Turner — American Economic Review: Papers & Proceedings, 104(5): 141–147 - **URL:** https://eml.berkeley.edu/~saez/chettyetalAERPP2014.pdf - **Published:** 2014-05 - **Validity:** Peer-reviewed study - **Summary:** Uses administrative earnings records for children born 1971–1993 to measure intergenerational mobility in the US. Introduces the rank-rank specification as a more robust measure than log-log IGE. Finds rank-rank slopes of approximately 0.30 (stable across cohorts) and IGE estimates ranging from 0.26 to 0.70 depending on model specification. Mobility has remained stable even as inequality widened — the "rungs of the ladder grew further apart but children's chances of climbing haven't changed." - **Key data points (time-referenced):** - 2014: Rank-rank slope ≈ 0.30 (stable across 1971–1986 birth cohorts), standard errors < 0.01 - 2014: IGE estimates range from 0.26 to 0.70 depending on specification (0.45 when excluding zero-income children) - 2014: Based on ~3.7 million children per birth cohort from US tax records ### Piraino (2015) — Intergenerational Earnings Mobility and Equality of Opportunity in South Africa - **Source:** Patrizio Piraino, World Development, Volume 67, pp. 396–405 - **URL:** https://ideas.repec.org/a/eee/wdevel/v67y2015icp396-405.html - **Published:** 2015-03 - **Validity:** Peer-reviewed study - **Summary:** The first nationally representative estimates of intergenerational earnings persistence in South Africa, using NIDS (waves 1–3) and PSLSD data with a two-sample two-stage least squares (TSTSLS) approach. Finds IGEs between 0.57 and 0.67 — indicating very low mobility. Race is shown to play a significant role in explaining earnings inequality. Places South Africa among high-inequality emerging economies with low mobility and low equality of opportunity. - **Key data points (time-referenced):** - 2015: South Africa IGE estimates range from 0.57 to 0.67 (using NIDS waves 1–3 and PSLSD) - 2015: A limited set of inherited circumstances (including race) explains a significant fraction of earnings inequality among male adults ### Finn, Leibbrandt & Ranchhod (2016) — Patterns of Persistence: Intergenerational Mobility and Education in South Africa - **Source:** Arden Finn, Murray Leibbrandt, Vimal Ranchhod — SALDRU Working Paper 175, University of Cape Town - **URL:** https://ideas.repec.org/p/ldr/wpaper/175.html - **Published:** 2016-08 - **Validity:** Peer-reviewed study - **Summary:** Uses NIDS waves 1–4 (2008–2014/15) and the 1993 PSLSD to investigate intergenerational earnings mobility in South Africa. Finds IGEs in the range of 0.61–0.68. The correlation between parent and child earnings is strongest at the top and bottom of the distribution. Correcting for selection into employment (given SA's high unemployment) increases the IGE by approximately 10%. Education accounts for approximately 40% of the total intergenerational earnings elasticity. - **Key data points (time-referenced):** - 2016: South Africa IGE estimates range from 0.61 to 0.68 (using NIDS waves 1–4 and PSLSD) - 2016: Correcting for selection into employment increases IGE by ~10% - 2016: Education accounts for ~40% of the total intergenerational earnings elasticity ### Razak (2026) — The Geography of Intergenerational Mobility in South Africa - **Source:** Aarifah Razak, UNU-WIDER Working Paper 2026/25 (ACEIR/SALDRU, University of Cape Town) - **URL:** https://www.wider.unu.edu/sites/default/files/Publications/Working-paper/PDF/wp2026-25-geography-intergenerational-mobility-South-Africa.pdf - **Published:** 2026-03 - **Validity:** Institutional report - **Summary:** The first study to estimate intergenerational income mobility at the district and metropolitan municipality level in South Africa, using NIDS (2008–2017) and Census 1996 with a TSTSLS approach. Reports national IGE estimates of 0.552–0.623 and rank-rank slopes of 0.264–0.294. Finds substantial spatial heterogeneity linked to former-homeland areas, racial segregation, crime, and school quality. Also cites Ressom (2025) finding IGEs of 0.65–0.83 using NIDS wave 5. - **Key data points (time-referenced):** - 2026: National IGE estimates 0.552 to 0.623; rank-rank slope 0.264 to 0.294 - 2025: Ressom (2025) documents IGEs of approximately 0.65 to 0.83 using NIDS wave 5 - 2026: Lower absolute upward mobility associated with higher crime, single-adult households, and racial segregation; higher mobility linked to family stability and quality schooling ### Branson & Ressom (2026) — Intergenerational Education Mobility Trends in South Africa - **Source:** Nicola Branson & Hagos Ressom, UNU-WIDER Working Paper 2026/34 (SALDRU, University of Cape Town) - **URL:** https://www.wider.unu.edu/sites/default/files/Publications/Working-paper/PDF/wp2026-34-intergenerational-education-mobility-trends-South-Africa.pdf - **Published:** 2026-04 - **Validity:** Institutional report - **Summary:** Examines intergenerational educational mobility across cohorts born 1953–1992 using NIDS wave 5, focusing on African, Coloured, and White population groups. Finds gains in upward mobility for African children (especially from low-education backgrounds), stagnation or decline for Coloured children, and persistent White advantages at the top. The education system does not yet function as an equalising force despite post-apartheid expansion. - **Key data points (time-referenced):** - 2026: Study covers cohorts born 1953–1992 using NIDS wave 5 - 2026: Gains in upward educational mobility for African children from low-education backgrounds; mobility among Coloured children has stagnated or declined - 2026: White children retain strong advantages at the top of the education distribution ### Piketty (2010) — On the Long-Run Evolution of Inheritance: France 1820–2050 - **Source:** Thomas Piketty, Paris School of Economics (published in QJE) - **URL:** http://piketty.pse.ens.fr/files/Piketty2010QJE.pdf - **Published:** 2010-05 (this version; published in Quarterly Journal of Economics 2011) - **Validity:** Peer-reviewed study - **Summary:** The foundational historical study of inheritance flows as a share of national income, tracing France from 1820 to 2010 with projections to 2050. Documents a U-shaped pattern: inheritance flows were 20–25% of national income in the 19th century, fell to less than 5% by 1950 after the World Wars, and rose back to ~15% by 2010. Projects a return to 20–25% by 2050. Demonstrates that when r > g (return on capital exceeds growth), past wealth and inheritance dominate aggregate wealth accumulation. - **Key data points (time-referenced):** - 1820–1910: Annual inheritance flow ≈ 20–25% of national income (France) - 1950: Annual inheritance flow falls to <5% of national income (France) - 2010: Annual inheritance flow recovers to ≈15% of national income (France) - 2050 (projected): Annual bequest flow could reach 20–25% of national income ### Alvaredo, Garbinti & Piketty (2017) — On the Share of Inheritance in Aggregate Wealth: Europe and the USA, 1900–2010 - **Source:** Facundo Alvaredo, Bertrand Garbinti, Thomas Piketty — Economica (2017) - **URL:** http://piketty.pse.ens.fr/files/AlvaredoGarbintiPiketty2017.pdf - **Published:** 2017-02 - **Validity:** Peer-reviewed study - **Summary:** Provides historical series on the share of inherited wealth in aggregate private wealth for France, the UK, Germany, Sweden, and the USA over 1900–2010. In Europe, the inheritance share was 70–80% around 1900–10, fell to 30–40% during 1950–80 after the capital shocks of 1914–45, and rose back to 50–60% by 2000–10. The US shows a similar but less pronounced U-shape with greater uncertainty for recent decades. - **Key data points (time-referenced):** - 1900–1910: Inheritance share of aggregate private wealth ≈ 70–80% in Europe - 1950–1980: Inheritance share falls to 30–40% in Europe - 2000–2010: Inheritance share rises to 50–60% in Europe (and rising) - 2000–2010: US pattern U-shaped but less marked, with significant uncertainty ### Credit Suisse — Global Wealth Report 2012 (Inheritance of Wealth Chapter) - **Source:** Credit Suisse Research Institute - **URL:** https://www.fondsprofessionell.de/upload/attach/1349864522.pdf - **Published:** 2012-10 - **Validity:** Institutional report - **Summary:** The 2012 edition of the Global Wealth Report included a dedicated chapter on "Inheritance of Wealth" — one of the few systematic attempts to estimate the share of inherited vs self-made wealth globally. Found that 69% of Forbes billionaires are self-made (less than one-third inherited), though excluding China/Russia/transition countries raises the inherited share to slightly above one-third. For all OECD households, estimated that 30–50% of wealth is inherited. Global household wealth totaled USD 223 trillion in mid-2012. - **Key data points (time-referenced):** - 2012: 69% of Forbes billionaires are self-made; <1/3 inherited their wealth - 2012: 30–50% of OECD household wealth estimated to be inherited - 2012: Global household wealth = USD 223 trillion (mid-2012, current exchange rates) ### UBS — Billionaire Ambitions Report 2023: The Great Wealth Transfer - **Source:** UBS Global Wealth Management - **URL:** https://www.ubs.com/global/en/media/display-page-ndp/en-20231130-great-wealth-transfer.html - **Published:** 2023-11-30 - **Validity:** Institutional report - **Summary:** The ninth edition of UBS's billionaire report found that, for the first time in nine editions, billionaires accumulated more wealth through inheritance than entrepreneurship. USD 150.8 billion was inherited by 53 heirs, exceeding the USD 140.7 billion accumulated by 84 new self-made billionaires. UBS projects that over 1,000 billionaires will pass an estimated USD 5.2 trillion to their children over the next 20 years, signaling an accelerating "great wealth transfer." - **Key data points (time-referenced):** - 2023: USD 150.8 billion inherited by 53 heirs vs USD 140.7 billion by 84 new self-made billionaires (first time inheritance exceeded entrepreneurship) - 2023: Over 1,000 billionaires expected to pass USD 5.2 trillion to children over next 20 years - 2023: 98% of billionaires in Mainland China are self-made (contrasting with global trend) --- ## Sources - **Kept: World Bank Fair Progress? (2018)** — Official statistics; foundational global mobility database (GDIM) with 148 economies. (https://www.worldbank.org/en/topic/poverty/publication/fair-progress-economic-mobility-across-generations-around-the-world) - **Kept: World Bank Intergenerational Income Mobility Database (2025)** — Official statistics; newest global IGE database, 87 countries, extends evidence to developing world. (https://documents1.worldbank.org/curated/en/099149507072519419/pdf/IDU-a6244ff6-f76f-41cb-8e51-f84b5491b362.pdf) - **Kept: OECD A Broken Social Elevator? (2018)** — Official statistics; provides the "generations to reach mean income" metric with South Africa at 9 generations (tied with Brazil). (https://www.oecd.org/content/dam/oecd/en/publications/reports/2018/06/a-broken-social-elevator-how-to-promote-social-mobility_g1g8e196/9789264301085-en.pdf) - **Kept: WEF Global Social Mobility Index (2020)** — Institutional report; the named composite index, South Africa ranked 77th of 82. (https://en.wikipedia.org/wiki/Global_Social_Mobility_Index) - **Kept: Corak (2013) JEP** — Peer-reviewed; the Great Gatsby Curve paper with IGE estimates for 22 countries. (http://piketty.pse.ens.fr/files/Corak2013.pdf) - **Kept: Charles & Hurst (2003) JPE** — Peer-reviewed; the canonical intergenerational *wealth* elasticity study (0.37). (https://erikhurst.com/wp-content/uploads/2020/02/charles_hurst_wealth_jpe.pdf) - **Kept: Chetty et al. (2014) AER** — Peer-reviewed; rank-rank mobility measure, US administrative data, slope ~0.30. (https://eml.berkeley.edu/~saez/chettyetalAERPP2014.pdf) - **Kept: Piraino (2015) World Development** — Peer-reviewed; first SA national IGE estimates (0.57–0.67). (https://ideas.repec.org/a/eee/wdevel/v67y2015icp396-405.html) - **Kept: Finn, Leibbrandt & Ranchhod (2016) SALDRU** — Peer-reviewed; SA IGE 0.61–0.68, education accounts for 40%. (https://ideas.repec.org/p/ldr/wpaper/175.html) - **Kept: Razak (2026) UNU-WIDER** — Institutional report; SA IGE 0.552–0.623, rank-rank 0.264–0.294, first subnational estimates. (https://www.wider.unu.edu/sites/default/files/Publications/Working-paper/PDF/wp2026-25-geography-intergenerational-mobility-South-Africa.pdf) - **Kept: Branson & Ressom (2026) UNU-WIDER** — Institutional report; SA education mobility trends by population group. (https://www.wider.unu.edu/sites/default/files/Publications/Working-paper/PDF/wp2026-34-intergenerational-education-mobility-trends-South-Africa.pdf) - **Kept: Piketty (2010/2011) QJE** — Peer-reviewed; historical inheritance flow series, France 1820–2050, U-shaped pattern. (http://piketty.pse.ens.fr/files/Piketty2010QJE.pdf) - **Kept: Alvaredo, Garbinti & Piketty (2017) Economica** — Peer-reviewed; inheritance share of aggregate wealth, Europe + US 1900–2010. (http://piketty.pse.ens.fr/files/AlvaredoGarbintiPiketty2017.pdf) - **Kept: Credit Suisse Global Wealth Report 2012** — Institutional report; inheritance chapter with self-made vs inherited billionaire and OECD wealth shares. (https://www.fondsprofessionell.de/upload/attach/1349864522.pdf) - **Kept: UBS Billionaire Ambitions Report 2023** — Institutional report; first year inherited wealth exceeded entrepreneurship for billionaires. (https://www.ubs.com/global/en/media/display-page-ndp/en-20231130-great-wealth-transfer.html) - **Dropped: OECD iLibrary full text** — Paywalled; could not access full text. Key data confirmed via Agência Brasil reporting on the same OECD data. - **Dropped: ScienceDirect (Piraino 2015)** — Paywalled; specific IGE numbers confirmed via Razak (2026) which cites them directly. - **Dropped: Slow Reveal Graphs blog** — Educational visualisation of OECD data; redundant with primary OECD source. - **Dropped: Zucman Econ 133 lecture slides** — Teaching material; secondary to primary sources already included. ## Gaps - **South Africa-specific IGE in the World Bank 2025 database (87 countries):** The paper mentions 87 countries and gives the range (0.14–0.96), but the specific South Africa value was not found in the text fetched. The dataset is publicly downloadable as a Stata file from the World Bank Data Catalog, which would contain the SA estimate. - **OECD specific IGE values by country from "Broken Social Elevator":** The full report is a large PDF that could not be fully extracted. The "generations to reach mean income" metric was verified via the Agência Brasil article, but the underlying IGE values per country (e.g., Denmark 0.15, US 0.47) cited in the Corak (2013) literature could not be independently confirmed from the OECD PDF itself. - **Credit Suisse/UBS Global Wealth Report — South Africa-specific inherited wealth share:** The 2012 report includes a South Africa country page, but the inheritance chapter focuses on global/OECD aggregates. No SA-specific inheritance share was found. - **WID.world South Africa inheritance flow data:** The WID database lists South Africa as a covered country, but specific inheritance flow as % of national income for SA was not found. WID's distributional national accounts focus primarily on income and wealth concentration, not inheritance flows specifically. - **Intergenerational wealth (not income) elasticity for South Africa:** All SA studies found measure income/earnings mobility, not wealth mobility. The Charles & Hurst (2003) wealth elasticity (0.37) is US-only. No SA equivalent was identified.