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Facundo Alvaredo, Lucas Chancel, Thomas Piketty, Emmanuel Saez, Gabriel Zucman · AEA Papers and Proceedings 108: 103-108

The Elephant Curve of Global Inequality and Growth

20 problems found: 1 major · 8 moderate · 11 minor

What the paper claims

Every problem found

1majorconfirmed · newly identified here · data error

The authors' computer code quietly replaced the Middle East's average income for 1980-84 with a figure almost half the size of the official statistics they had loaded, without any explanation. Because the rich of the Gulf oil states were among the world's top earners in 1980, making them poorer in 1980 makes the world's richest look as if their incomes grew much faster afterwards. Undoing the change cuts the reported growth of the world's richest by about a fifth, although the richest 1% still gained about twice the poorer half's share of growth.

Technical detail and evidence

Why it matters, in detail. Pure level shift of one of 15 subregional distributions in 1980-84 (shares unchanged). MENA residents are 17.8% of the 1980 global top 0.001% with the override and 35.8% without; a 45% cut of their 1980 incomes lowers 1980 top fractiles and raises 1980-2016 top-end growth. Direction: inflates the trunk (C2/C3) and the top-share trend (C4). Magnitude: top-1% growth +21 pp, top-0.001% growth +51 pp, world average growth +5.8 pp, top-1% share rise +1.27 pp (3.01 -> 4.28 pp); capture ratio +0.19 (2.00 -> 2.19). Three independent merges agree within ~1-2 pp.

Evidence. Code: computer-codes.zip, Do/'0c - aggregate-regions.do' lines 62-67. Adjudicator's Python translation of 0b/0c (scripts/rebuild_regions.py) reproduces the stored regions-aggregates.dta to 6.5e-8 only with the override; without it, only MENA 1980-84 differ. MENA income per adult (2016 PPP EUR) in the imported data: 20,566 (1980), 19,906, 18,349, 17,651, 17,454 (1984), 16,998 (1985); used: 11,332 for 1980-84. MENA growth 1980-2016: +4.1% in the data vs +88.8% used (Technical Note Table B1 'Middle-East 89%'). Saudi Arabia supplies 32.6% of MENA 1980 income (EUR 142,765 per adult in 1980, 72,876 in 1985). WDI real GDP per capita 1985/1980: MENA aggregate 0.85, Arab World 0.78, Saudi Arabia 0.51, Kuwait 0.62, UAE 0.69, Qatar 0.71. Current WID MENA (XN, bulk 2026-10-15): x0.835 over 1980-85, +4.7% over 1980-2016. Effect on world 1980-2016 growth (adjudicator's validated merge, scripts/experiments.py), published inputs -> MENA = national accounts: average 58.9 -> 53.2%; bottom 50% 94.1 -> 87.8%; middle 40% 40.9 -> 38.5%; top 10% 69.1 -> 60.1%; top 1% 101.1 -> 79.6%; top 0.1% 132.8 -> 93.8%; top 0.01% 183.9 -> 139.6%; top 0.001% 234.1 -> 183.1%. Global top-1% share 1980: 16.16 -> 17.43%, so the 1980-2016 rise falls from 4.28 to 3.01 pp (-30%). Capture top 1% / bottom 50%: 27.71 / 12.65 -> 26.10 / 13.03 (ratio 2.19 -> 2.00). Neutral 'flat at 1985' variant: top 1% 87.8%, top 0.001% 202%, ratio 2.09. The override also creates most of the 1984->85 jump in Figure 3's top-1% series (16.18 -> 16.96 with it; 16.88 -> 16.96 without). Both auditors obtained the same numbers independently (A: top 1% 79.7%, top 0.001% 184.7%; B: top-1% share rise -29.8%, capture 26.10/13.03).

Why this severity. Restoring the authors' own imported national accounts lowers the reported top-1% and top-0.001% growth rates by about a fifth (101% -> 80%; 234% -> 183%) and the 1980-2016 rise in the global top-1% share by 30%, i.e. roughly a quarter of core top-end magnitudes, and the bottom 50% then grows faster than the top 1% (88% vs 80%). The capture headline (2.0x) and the qualitative elephant shape survive, so the problem is major, not critical.

2moderateconfirmed · previously known · speculative assumption

For about a fifth of the world's adults (Japan, Indonesia, Pakistan, Bangladesh and other Asian countries without good data) the authors simply copied the pattern of inequality from China and India. That shortcut implies that the poorer half of these countries became 20% poorer after 1980, which is hard to square with the large falls in poverty there. With the authors' own alternative method, the richest 1% gained about 1.7 times, not twice, the poorer half's share of global growth, although the authors' newer data put it back at about twice.

Technical detail and evidence

Why it matters, in detail. Static calibration transfers China+India share levels (including the within-pair between-country divergence) to a region with 60% mean growth, forcing negative absolute growth for ~470m bottom-half adults; this lowers global bottom-50% growth and capture. Range across defensible variants: capture ratio 1.46-2.19 (1.50 combined with F1), bottom-50% growth 94-127%, top-1% growth 91-101% (73% combined with F1). External check: current WID ratio 2.20, bottom-50% growth 95%, i.e. the published values are within the range and close to the later estimate.

Evidence. '1d - calibrate-subregions.do' (calibration=0 branch copies shares; the dynamic branch's header comment notes that otherwise the 'bottom 50% see its average income decrease'); Technical Note 2017/5 Section 3.5 and Appendix C (Tables C1-C2: world bottom-50% growth 115%, top 1% 94%, captured 25.77% vs 15%). Adjudicator recomputation (scripts/diagnostics.py, scripts/experiments.py): Other Asia static bottom-50% -19.8%, top 1% +247%; dynamic +24.4%; Other North America static bottom-50% -10.8%. World capture ratio: static 2.19; authors' dynamic file 1.67 (25.77/15.47; reproduces TN Appendix C exactly); dynamic + MENA national accounts 1.50 (24.03/16.04; bottom 50% grows 108% vs top 1% 73%); Other Asia held at the China+India 1980 shape 1.46 (24.83/17.03). Auditor A reports steep falls in World Bank $3/day poverty in Indonesia, Bangladesh, Pakistan and Thailand (not re-run here). Current WID (WO-PPP, bulk 2026-10-15): capture 27.15% vs 12.35% (ratio 2.20), bottom-50% growth 95%.

Why this severity. Within the 2018 inputs, the authors' own alternative cuts the headline capture ratio by about a quarter (2.19 -> 1.67) and raises bottom-half growth from 94% to 115%; but the later WID vintage, which uses direct data for more Asian countries, reproduces 27% vs 12% and 95% bottom-half growth, so no bias in the published headline is demonstrated. It is an important sensitivity that the paper does not disclose rather than a demonstrated error, and the top 1% captures far more than the bottom 50% in every variant (24-28% vs 12-17%). Auditor A rated it major.

The authors' response. Technical Note 2017/5 Section 3.5 acknowledges that the static method 'could lead to underestimating the growth rate of the average income of the Bottom 50%' and reports the dynamic alternative as 'qualitatively similar' ('the elephant curve is in fact even more pronounced'); the P&P (p. 104) calls the regional assumption 'obviously an over simplification'; Chancel & Piketty (2021, JEEA 19(6), pp. 3055-3056) state that reliance on a limited set of countries 'can certainly affect some of the finer decompositions for the more recent period'.

3moderateconfirmed · newly identified here · methodology

To project incomes to 2050, the authors assume each income group keeps getting the same slice of growth it got since 1980; where that slice was negative, the code quietly sets it to zero. Whether the poorer half of the world loses or holds its share of income under 'business as usual' turns on this unexplained rule and on the copied inequality pattern for Asia, so that particular forecast is not reliable, even though the comparison between the three scenarios is.

Technical detail and evidence

Why it matters, in detail. Clipping negative growth shares and rescaling raises the BAU 2050 bottom-50% mean by 16% relative to a floor-at-zero rule (EUR 6,219 vs 5,364) and its share by 1.2 pp; but the negative shares for Other Asia and Other North America are artefacts of the static proxy (F2), and replacing them with donor growth profiles raises the BAU 2050 bottom-50% share to 9.95% (+1.2 pp) and mean to EUR 7,095 (+14%). The BAU bottom-half trajectory is therefore not identified by the data.

Evidence. '6c - project-regions.do' lines 17-37 (replace share=0 if share<0) and 94-104 (rescaling); '0d - import-shares-growth.do' lines 141-149 (US donor is 1980-2015, not 1980-2016). The adjudicator's re-implementation of 6a (PPP) + 6c (scripts/proj6.py) reproduces the authors' project-regions.dta to 7e-7 in all three scenarios, and merged world results match gpinterized-projections.dta (BAU 2050 bottom-50% share 8.72%, top 1% 24.52%, bottom-50% income EUR 6,219). Variants (scripts/projection_variants.py): no clipping, final incomes floored at zero (rank weights repaired): BAU bottom-50% share 7.52%, top 1% 25.18%, bottom-50% income EUR 5,364 (Auditor B: 7.53%, EUR 5,373); Other Asia given the China+India 1980-2016 growth profile and Other North America the US profile: BAU bottom-50% share 9.95%, top 1% 23.52%, income EUR 7,095 (Auditor A: 9.95%, 23.5%, EUR 7,096). US and EU scenarios move by at most ~4%.

Why this severity. Affects a secondary (projection) result: the sign of the projected BAU change in the global bottom-50% share is not robust (7.5% to 10.0% in 2050 vs 9.7% in 2016) and BAU 2050 bottom-half income varies by about +/-14%; the rise of the top-1% share under BAU (23.5-25.4%) and the ranking of scenarios survive.

4moderateconfirmed · previously known · documentation gap

For several regions the authors have no data on how income was shared out in 1980, so they assume it was shared the same way as in the first year they do have data (2001 for Latin America, 1990 for the Middle East). More than half of the world's very richest people in 1980 in these figures come from these assumed distributions, so the starting point for measuring how fast the richest grew is largely a guess.

Technical detail and evidence

Why it matters, in detail. Top-end growth is the ratio of 2016 to 1980 top-fractile incomes; more than half of the 1980 denominator for the global top 0.001% consists of Latin American and MENA tails extrapolated from 2001 and 1990 shapes, so any true 1980-2001 change in Latin American (or 1980-90 MENA) top shares passes almost one-for-one into the global trunk. Sign and size unknown.

Evidence. wid2017_subset (extract of the frozen 2017 WID input database): Brazil top-10% share observed 2001-2015; UK 1990-2014 (individual series only); Germany 18 years between 1961 and 2013. Authors' inputs (1d-calibrate-subregions.dta): Brazil top-10% share 54.34% in every year 1980-2001; MENA 65.11% in 1980-89. Workbook Figure1A-data C14:C24: Brazil 58.09% (1990) -> 54.03% (2000). Composition of the 1980 global top 0.001% (adjudicator merge, scripts/diagnostics.py): Other Latin America 26.5%, MENA 17.8%, Brazil 12.8% (together 57.1%); of the top 1%: 25.0%. The P&P (p. 104) gives 1990 as 'the first year for which we can construct estimates' for the Middle East, Brazil and sub-Saharan Africa.

Why this severity. The 1980 base of the trunk and of the top-1% share rests mostly on assumed (constant-share) distributions; the direction of any bias is not demonstrated (constant shares are conservative where inequality rose, but this is untested for Latin America and MENA), so this is an important undisclosed caveat on the magnitudes in C2-C4 rather than a demonstrated error.

The authors' response. Technical Note 2017/5 Section 2.4 describes the constant-share extrapolation and calls it 'conservative' 'in the context of a general rise in inequality since the 1980s'.

5moderateconfirmed · newly identified here · external inconsistency

When the same calculation is redone with the newer version of the authors' own database, the headline result (the richest 1% got about twice the poorer half's share of growth) comes out the same, but growth for the very richest is much smaller: about 130% rather than 235% for the top 0.001%. The 2018 numbers for the very top should therefore be treated as uncertain.

Technical detail and evidence

Why it matters, in detail. The later vintage (new country DINA series, revised PPPs and national accounts, a MENA series without the 1980-84 cut) lowers top-group growth by 26-44% and middle-40% growth by 11 pp; the top 0.001% now grows about as much as the hump of the curve (131% vs ~120% in the paper), i.e. the 'long trunk' largely disappears, while capture shares (27.2% vs 12.4%) are unchanged.

Evidence. WID bulk download 2026-10-15, WO-PPP, sptincj992 x anninci992 (scripts/current_wid_check.py): average growth 46.2% (paper 60%), bottom 50% 95.2% (94%), middle 40% 32.2% (43%), top 10% 52.0% (70%), top 1% 74.6% (101%), top 0.1% 97.5% (133%), top 0.01% 121.4% (185%), top 0.001% 131.5% (235%); capture top 1% 27.15%, bottom 50% 12.35%; top-1% share 16.8% (1980), 21.6% (2007), 20.1% (2016); bottom-50% share 6.0% (1980) -> 8.0% (2016) vs 8.0% -> 9.7%. Auditor A obtained the same (top 0.001% 124.9% using a slightly different bracket construction).

Why this severity. The authors' own later estimates put top-1% growth about a quarter lower and top-0.001% growth about 45% lower, so the trunk magnitudes in C2/C3 must be read as fragile; the C1 headline is corroborated. Not counted as an error of the 2018 paper.

The authors' response. Technical Note 2017/5 (p. 5) advises replicators to use the frozen September 2017 database because the online version 'is regularly updated' and 'may generate slightly different estimates'; Chancel & Piketty (2021, pp. 3055-3056) say new country series can affect 'finer decompositions for the more recent period'.

6moderateconfirmed · previously known · methodology

For regions without data, the code treats, for example, all of 'Other Asia', from rich Japan to poor Bangladesh, as if it were one country with a single average income, hiding the large gaps between those countries. Fixing this does not change the headline, but it moves the 'hump' of the elephant towards the middle of the world distribution and makes the global poorer half look poorer.

Technical detail and evidence

Why it matters, in detail. Block-merging removes within-subregion between-country dispersion (Japan had 19% of Other Asia's adults but 46% of its income in 1980) and substitutes the donor's dispersion. With country means, the 1980 global bottom half is poorer and the 2016 middle richer, shifting the hump right and deepening the trough. Upper-bound caveat: applying the China+India shape (which already contains the China-India gap) country by country double counts part of the between-country dispersion.

Evidence. Code 1b, 1c, 1d, 1g; 0c lines 27-37 (USSR fill). Technical Note Section 3.1 ('the between-country component of inequality is properly estimated') and Section 3.3 ('We performed tests where we combined a larger number of countries, and as expected, results were very similar'). Adjudicator test (scripts/country_means.py: each country's own 1980/2016 national income per adult and adult population from the authors' files, donor shape unchanged): bottom-50% share 7.92% -> 6.80% (1980) and 9.67% -> 8.88% (2016); top-1% share 2016 20.44% -> 21.07%; bottom-50% growth 94% -> 108%; hump 120% at p25 -> 124% at p38; median growth 62% -> 110%; mean growth p40-p60 68% -> 106%; trough 36.7% at p75 -> 31.6% at p81; capture ratio 2.19 -> 2.30 (dynamic calibration 1.67 -> 1.83). Auditor A's E8 gave the same within ~1 pp.

Why this severity. Moves the hump of Figure 2 from p25 to p38, raises median growth from 62% to 110% and lowers the bottom-50% share level by about 1 pp, which are noticeable features of Figures 2-3; the change makes the elephant more pronounced and leaves the capture headline essentially unchanged, so it does not undermine the core findings.

The authors' response. Technical Note 2017/5 Section 3.3: merging country by country 'would be computationally very intensive and would not add much'; tests combining more countries gave 'very similar' results.

7moderateconfirmed · newly identified here · replication failure

Using the authors' posted code and results, most headline numbers can be recovered, but the 'European-style' forecast cannot: it gives the poorer half about EUR 8,350 a year in 2050 rather than the EUR 9,100 printed, so their income would be about 1.9 times, not twice, that in the 'US-style' world. The journal's official replication package could not be opened.

Technical detail and evidence

Why it matters, in detail. The archive's EU8016 growth profile gives a 2050 bottom-50% share of 11.7% and mean of EUR 8,350 (EU/US 1.86); the published 12.9%/EUR 9,138 lies between the archive's EU8016 and FR8015 results and is unreconciled. Other world-level differences (<= 2 pp) are consistent with a later final run.

Evidence. World column, archive vs published: average 58.9 vs 60, middle 40% 40.9 vs 43, top 10% 69.1 vs 70, top 0.01% 183.8 vs 185, top 0.001% 234.4 vs 235; capture 27.71/12.65 vs 27/12 (the technical note's Figure B2 key says 28%/13%; workbook-implied values 27.32/12.45). EU scenario 2050: bottom-50% share 11.71% (archive; adjudicator merge of project-regions.dta identical) vs 12.88% (workbook Figure3-data C75); bottom-50% income EUR 8,350 vs 9,138 (Figure4-data E74), -8.6%; EU/US income ratio 1.86 vs 2.04 ('twice higher'); top 1% 19.35% vs 19.05%. Neither archived European profile reproduces the published values (EU8016: 11.71%, EUR 8,350; FR8015: 14.51%, EUR 10,353). BAU EUR 6,219 vs 6,299; US EUR 4,479 vs 4,479 (exact). Figure 1's Europe top-10% series differs from the archive's Europe aggregate by up to 2.4 pp (other regions match within 0.15 pp); Brazil 1990-2000 differs (F4). DataCite: deposit created 2025-05-31; openICPSR returned HTTP 403 (Cloudflare) to the adjudicator and to both auditors.

Why this severity. Core world numbers reproduce within 1-2 pp, but the European-scenario numbers quoted in the text (about 13%, EUR 9,100, 'twice higher') cannot be obtained from the posted materials, and no reconciling package is accessible; this weakens a secondary result and the paper's statement that 'all data and programs are available online at WID.world'.

8moderateconfirmed · newly identified here · internal inconsistency

The paper says that neither fast growth in emerging countries nor the 2008 crisis stopped world inequality from rising. Its own chart shows otherwise: after 2007 the richest 1%'s share of world income fell back below its 2000 level, and the poorer half's share went up. What did keep rising was inequality inside countries, which is a different claim.

Technical detail and evidence

Why it matters, in detail. Global top-1% share -0.53 pp over 2000-2016 and -1.76 pp over 2007-2016; bottom-50% share +0.98 pp over 2000-2016; top-10% share -3.2 pp. The defensible statement (within-country inequality kept rising while between-country inequality fell) is in the WP abstract but not in the P&P.

Evidence. Workbook Figure3-data: top-1% share I25 = 20.97% (2000), I31 = 22.22% (2006), I32 = 22.20% (2007), I41 = 20.43% (2016); bottom-50% share E25 = 8.68% (2000), E41 = 9.66% (2016). Archive: global top-10% share 55.3% (2000) -> 52.1% (2016); Gini 0.677 -> 0.652 (Auditor B). WP 2017/20 (long version) abstract: 'We observe a trend-break after the financial crisis, but this is only due to between-country reduction in inequality, as within-country inequality continued to rise'; Section 4: 'the situation more or less stabilized beginning in the early 2000s'. Chancel & Piketty (2021, Figure 8 caption): 'the decline in global inequality observed since 2008'. Current WID: top-1% share 21.6% (2007) -> 20.1% (2016).

Why this severity. A stated conclusion about the post-2000 trend is the opposite of what the paper's own Figure 3 series show; it does not affect the 1980-2016 estimates, so its impact on the core findings is limited, but it misstates a secondary result and frames the projections.

The authors' response. The working paper's own abstract acknowledges 'a trend-break after the financial crisis', attributing it to between-country convergence; Chancel & Piketty (2021) refer to 'the decline in global inequality observed since 2008'.

9moderateplausible · previously known · speculative assumption

For whole regions such as the Middle East and sub-Saharan Africa, the incomes of the richest are estimated from tax data of a single country (Lebanon, Cote d'Ivoire) and applied to all the others. Critics have argued this can overstate or misplace top incomes; nobody has yet measured how much it changes the global picture, so it remains an open uncertainty rather than a proven error.

Technical detail and evidence

Why it matters, in detail. Donor-tail and proportional-scaling assumptions determine where the national-accounts/survey gap is allocated; in MENA the Lebanese tail shapes a population that is a large share of the global top in 1980. Direction and size for the global curve are not established; Yonzan et al. (2022) support tax-based corrections for the top 1% in rich countries but not wholesale replacement of upper-decile survey data.

Evidence. P&P p. 103 and footnote 2; Technical Note Section 2.3. MENA residents are 17.8% of the 1980 global top 0.001% (35.8% at national-accounts incomes, F1) and 8.7% in 2016 (adjudicator merge). The current WID MENA top-1% share falls from 33.7% (1980) to 22.9% (2016), indicating large later revisions to these tails. Kharas & Seidel (2018, Brookings WP 114): WID uses distributional data 'for just 53 countries covering 65 percent of the world's population'; Lebanon's top data 'applied to all other countries' of the Middle East and Cote d'Ivoire's to Africa (fn 28).

Why this severity. Plausibly affects the level and growth of the global top, which drives the trunk and part of the capture headline, but neither the critics nor this adjudication quantify the effect on the global curve, and the survey-based comparators are not concept-matched; an important caveat rather than a demonstrated bias.

The authors' response. Chancel & Piketty (2021, JEEA, pp. 3055-3056) acknowledge that corrections 'often rely on a limited set of countries' but say their robustness checks show this does not affect the general long-run conclusions; per the critique corpus, Alvaredo, Assouad & Piketty (2019, fn 10) reply that Hlasny & Verme's survey-based Pareto benchmarks are 'artificially low' (not re-verified here).

10minorconfirmed · newly identified here · data error

When projecting to 2050, the code grows the number of adults at the rate of the whole population, but because populations are ageing, the number of adults grows faster. This makes future income per adult look about 10% higher than it should, though it does not change which scenario is more or less unequal.

Technical detail and evidence

Why it matters, in detail. Denominator error in projected income per adult: 2050 adult counts understated by ~13% in aggregate, so per-adult means and bottom-50% means are overstated by 7-10%; distributional shares are essentially unaffected because growth shares are applied to totals. Magnitude approximate (current WPP age structures stand in for WPP 2017).

Evidence. projections.dta, 2016: China 1,403.5m, India 1,324.2m, US 322.2m, Nigeria 186.0m (total population) vs WID adults 1,067.3m, 826.3m, 234.8m, 85.4m (populations.dta); '6a - import-projections.do' line 18. World Bank (WPP-based, current revision) 2016-2050: total population x1.280, adults 20+ x1.427 (ratio 1.115; India 1.22, Nigeria 1.30). Re-running 6a/6c with 20+ growth (scripts/projection_variants.py, P3): world adults 2050 6.06bn -> 6.95bn; world average per adult EUR 35,661 -> 32,800; 2050 bottom-50% income BAU EUR 6,219 -> 5,692, US 4,479 -> 4,180, EU 8,350 -> 7,542; shares nearly unchanged (BAU top 1% 24.71%, bottom 50% 8.68%). Auditor A obtained the same within 1%.

Why this severity. Lowers projected 2050 bottom-half incomes by 7-10% ('double again' becomes about +85%) but leaves shares, the scenario ranking and all conclusions unchanged; Auditor A rated it moderate.

11minorconfirmed · newly identified here · data error

A formula used to fill in missing data for Germany and the UK was written upside down. It barely changes the world results, but it makes Europe's richest look as if they grew somewhat more slowly than the authors' method would otherwise imply.

Technical detail and evidence

Why it matters, in detail. Inverse scaling misallocates income between the bottom 90% and top 10% of Germany and the UK in opposite directions; the errors largely cancel in the FR-DE-UK donor and in world aggregates (<0.3 pp on top-1% growth; capture unchanged) but understate European top-end growth.

Evidence. '1a - prepare-data.do' line 232: replace ainc = afr * (avg90fr/avg90) if p<90000. Adjudicator check (scripts/degb_fix.py): UK 1980 top-10% share 28.3% in the inputs vs 37.1% intended; Germany 1980 35.8% vs 31.9% (WID-2017 31.86%); UK 1980 bottom-90% average EUR 22,858 vs 15,327 intended. Correcting it: world top-1% growth 101.1 -> 101.3%, top-0.001% 233.9 -> 239.1%, capture unchanged (27.74/12.65); Europe column of Table 1: bottom 50% 26.3 -> 28.8%, top 10% 58.0 -> 55.3%, top 1% 71.9 -> 73.6%, top 0.1% 76.3 -> 84.8%, top 0.01% 87.7 -> 101.7%, top 0.001% 118.7 -> 137.7%. Both auditors found the same error (B: European bottom-50% growth 26.28 -> 28.42%).

Why this severity. A confirmed coding error with negligible effect on world results and a modest effect on the Europe column (top-end growth up by 2-19 pp); Europe still has the smallest gap between bottom and top growth. Auditor B rated it moderate.

The authors' response. Technical Note Section 2.2 calls the UK/Germany imputation provisional and says alternative specifications 'had only very little impacts'.

12minorconfirmed · newly identified here · internal inconsistency

The growth numbers the paper prints for North America and Russia are not the ones its own world calculation uses. The mismatch is small for the world results but means the regional table and the world figures are not fully consistent.

Technical detail and evidence

Why it matters, in detail. The world merge embeds ~8 pp faster US-Canada average growth than Table 1 reports and treats Russia+Ukraine as one block; consistent harmonization would lower world average and top-group growth slightly and leave capture shares unchanged.

Evidence. Technical Note Table B1 (archive): North America 71%, Ex-USSR 16% (with group rows 8/50/135/224/347/488/684 and -36/-9/151/579/2200/7105/21820), vs P&P Table 1 US-Canada 63/5/44/123/206/320/452/629 and Russia 34/-26/5/190/686/2562/8239/25269. wid2017_subset: US anninc992i +72.2% (1980-2014), +74.5% (1980-2016); Ukraine -41.7%. Auditor A: PSZ (2018) US +60.8% over 1980-2014; harmonizing US-Canada to 63% gives world average 57.3%, top-1% growth 97.9%, capture 27.8%/12.9% (A's E7, not re-run).

Why this severity. An undisclosed inconsistency between a reported regional table and the inputs of the world computation, with small effects on world results (per Auditor A's harmonization, top-1% growth -3 pp) and no effect on conclusions.

13minorconfirmed · newly identified here · overclaiming

The authors chose growth rates for Africa, Latin America and parts of Asia that are higher than official forecasts, and say so. That choice is cautious for their inequality conclusions, but it also makes the predicted incomes of the world's poorer half in 2050 look 13-24% higher.

Technical detail and evidence

Why it matters, in detail. Higher imposed mean growth in poorer subregions mechanically raises global bottom-half levels (+13-24% by 2050) and the bottom-50% share (+0.8 pp in BAU), and slightly raises the BAU top-1% share because of the Other Asia growth-share profile (+0.3 pp).

Evidence. '6a - import-projections.do' lines 31-48; adjudicator variant without the overrides (scripts/projection_variants.py, P4): 2050 bottom-50% income BAU EUR 5,241 (vs 6,219), US 3,959 (vs 4,479), EU 6,754 (vs 8,350); BAU bottom-50% share 7.96% (vs 8.72%); BAU top-1% share 24.22% (vs 24.52%). Auditor A obtained identical figures.

Why this severity. The assumption is disclosed and is indeed conservative for inequality shares; the only problem is that the headline income levels ('double again, to EUR 6,300') depend on it, which the footnote does not make clear.

The authors' response. Disclosed in footnote 4 and Technical Note Section 4.1 ('We view this relative optimism as a conservative assumption').

14minorconfirmed · newly identified here · data error

The Middle East figures for the early 1980s contain internal inconsistencies that the code patches automatically. The patch slightly understates how fast the world's richest grew, so it works against the authors' conclusion, and only by a little.

Technical detail and evidence

Why it matters, in detail. The data repair concentrates MENA 1980 income at the top (+5.8 pp top-10% share), raising 1980 global top fractiles; correcting it would raise world top-1% growth by ~3 pp (Auditor A).

Evidence. Data/Added/middle-east.dta: 112 inconsistent brackets in 1980 (e.g. bracket average above the next threshold); top-10% share 65.1% in the source vs 70.9% after the force-format step (1984: 65.6%; 1985: 65.0%; 1990: no inconsistencies). Auditor A: correcting it raises world top-1% growth to 104% and, combined with F1, gives 85%.

Why this severity. Small and in the direction opposite to F1 (it raises the 1980 global top and so lowers measured top-end growth).

15minorconfirmed · previously known · overclaiming

The paper concludes that growth alone will not lift the poorer half of the world out of poverty. Its numbers only show the average income of that group under different scenarios; they do not say how many people would be poor, so the poverty conclusion goes beyond the evidence, even though the point that inequality affects poorer people's incomes is supported.

Technical detail and evidence

Why it matters, in detail. Scenario differences in the bottom-50% mean are established; mapping them to poverty requires a poverty line and the within-bottom-half distribution, neither of which is reported.

Evidence. P&P p. 108 (opening paragraph) and Figure 4. All three scenarios raise the bottom-50% mean above its 2016 level (EUR 4,479-9,138 vs 3,082). Auditor B's illustrative counterexample: two distributions with identical bottom-half means (EUR 4,500) but 0% vs 25% below an illustrative threshold. Concept difference: Kharas & Seidel (2018) on pre-tax income vs consumption.

Why this severity. An interpretive overreach in a concluding sentence; the conditional result it rests on (bottom-half average income differs about 1.9-2x between the EU- and US-style scenarios) is reproduced and is the defensible statement. Auditor B rated it moderate.

16minorconfirmed · previously known · overclaiming

The chart labels the dip in the middle of the elephant as the squeezed working and middle classes of the US and Western Europe. In 1980, though, most people at that point of the world distribution lived elsewhere, especially in the former Soviet Union and Asia, so the label tells only part of the story.

Technical detail and evidence

Why it matters, in detail. The trough mixes the collapse of ex-Soviet incomes, the imputed Other Asia distribution and rich-country stagnation; attribution to the US/Western Europe alone overstates their role.

Evidence. Adjudicator composition of the 1980 global p70-p90 band (scripts/diagnostics.py): Other Asia 22.0%, Russia+Ukraine 19.2%, Other Western Europe 12.1%, US 11.1%, Eastern Europe 7.3%, Germany 5.4%, UK 4.0%, France 3.7%, Other North America 1.3% (US+Canada+Western Europe 37.7%); 2016: China 27.6%. Table 1 does show low US-Canada and European bottom-50% growth (5%, 26%).

Why this severity. A labelling simplification common to anonymous growth curves; the underlying pattern (slow growth for rich-country lower and middle classes) is real in Table 1, and the trough's position relative to the mean is not an artefact of population growth (see rejected claims).

17minorconfirmed · newly identified here · arithmetic or transcription

Several labels and descriptions are wrong or inconsistent, for example two of the euro amounts printed on Figure 4 and which scenario is called 'second'. None of them changes the results.

Technical detail and evidence

Why it matters, in detail. No effect on estimates; the abstract's 'at the median' would only be accurate under country-level means (F6) or in the later vintage (hump at p46).

Evidence. P&P p. 107 Figure 4 (page image checked) vs workbook Figure4-data D74 = 6,299.2, C74 = 4,479.2 and text p. 107; P&P p. 107 text vs Figure 3-4 legends; AEA abstract vs workbook Figure2-data B44 = 62.04 (p50), B19 = 119.96 (p25); workbook Figure1A-data F37:F40 = 55.456; WP 2017/20 (December 2017, long version, eml.berkeley.edu/~saez/ACPSZ2018WIDWP.pdf), Section 3: 'income growth was lower than 100% (40%, 34%, and 74%, respectively)', 'the global average (+66%)' and Europe 'excluding Ukraine, Belorussia, and Russia'; '0b - import-regions.do' line 20; User Guide 2017/9 description of 1d (calibration = 1 described as rescaling) vs its own option list (static 0, dynamic 1) and the code.

Why this severity. Presentation slips with no effect on computed results; the text values are the correct ones.

18minorconfirmed · newly identified here · arithmetic or transcription

A worked example in the technical appendix contains a simple arithmetic mistake (4% instead of 40%); the paper's actual calculations do not repeat it.

Technical detail and evidence

Why it matters, in detail. No propagation into any estimate.

Evidence. Technical Note 2017/5, Section 3.5 (p. 15 of the PDF), worked example; the formula in the code ('2a - world-shares-growth.do', '1d') and in the adjudicator's recomputation is correct.

Why this severity. An arithmetic slip in an illustrative example in the companion note; the empirical 27%/12% use the correct formula.

19minorconfirmed · newly identified here · documentation gap

Australia, New Zealand and the Pacific islands are accidentally left out of the 'world', despite the claim that all global income is covered. They are a small share of the world, so the results barely change.

Technical detail and evidence

Why it matters, in detail. Omitting a small high-income region slightly lowers world mean levels; including it changes world group growth by <0.7 pp and capture shares by <0.1 pp.

Evidence. 'runwir-program.do' line 92 ($countries = AF AS BR CN DE EE FR GB IN ME NA RU SA US WE); '0c - aggregate-regions.do' lines 54-60 keep only listed regions; regions-aggregates.dta contains no OC rows. Dropped: 13.7m adults (0.57%) and 1.17% of world income in 1980; 26.9m adults (0.55%) and 1.09% in 2016 (Australia 18.1m adults at EUR 38,977; New Zealand 3.3m; Papua New Guinea 4.1m) (scripts/rebuild_regions.py). Technical Note Table A1 (Scenario 4: 100% of population and income); P&P p. 103. Adding Oceania with the Western European shape (scripts/experiments.py, E5): capture ratio 2.19 unchanged; top-1% growth 100.9%; top-0.001% 233.4%.

Why this severity. A coverage misstatement with no material effect on any reported result.

20minorplausible · newly identified here · overclaiming

The paper says that rising inequality is driven by policy rather than by globalization or technology, but the evidence shown in this paper is only that inequality rose more where policies changed more, which does not prove cause and effect.

Technical detail and evidence

Why it matters, in detail. Cross-sectional co-movement of inequality and policy across five or six regions cannot separate policy from other region-specific shocks; no identification is offered.

Evidence. P&P p. 104, first column; Figure 1.

Why this severity. An interpretive claim outside the paper's quantitative findings; it may be defensible on the basis of the authors' country studies but is not established here.

Claims examined and rejected

Problems one auditor raised that did not survive checking.

Audit notes

What reproduced. Reproduced: (1) every number in the text against the authors' workbook (workbook-implied capture 27.32% vs 12.45%, world growth 60.4%, top-1% share 16.28% -> 22.20% -> 20.43%, bottom-50% income EUR 1,586 -> 3,082), except the Figure 4 labels; (2) the authors' gpinter world distribution with the adjudicator's independent merge of the 15 subregional inputs (1980-2016 group growth within 0.3 pp, capture 27.71%/12.65% identical, shares within 0.01 pp, curve mean absolute difference 0.16 pp); the archive is a slightly earlier vintage than the published figures (world middle 40% 40.9% vs 43%, average 58.9% vs 60%); (3) the regional aggregates from country data (6.5e-8, only with the MENA override); (4) the technical note's dynamic-calibration robustness numbers (B50 115%, top 1% 94%, capture 25.77%/15.47%); (5) the projection step (6a PPP + 6c) to 7e-7 against project-regions.dta, the US 2050 scenario exactly and BAU closely (EUR 6,219 vs 6,299). Not reproduced: the European 2050 scenario (bottom-50% share 11.71% vs 12.88%, income EUR 8,350 vs 9,138, EU/US 1.86 vs 2.04), Table 1's US-Canada (71% in inputs vs 63%) and Russia (16% for the Russia+Ukraine block vs 34%) columns, Figure 1's Europe and Brazil 1990-2000 series. The AEA openICPSR deposit (created 2025-05-31) was inaccessible (HTTP 403). Sensitivity: MENA override removed -> top 1% 79.6%, top 0.001% 183%, ratio 2.00; authors' dynamic calibration -> ratio 1.67; both -> 1.50; country-level means -> 2.30; adding Oceania -> 2.19; Germany/UK fix -> 2.19; market exchange rates -> 4.2 (static); current WID -> 2.20 with top 1% 74.6% and top 0.001% 131.5%.

Limits of this audit. The AEA/openICPSR deposit (10.3886/E231566V1, created 2025-05-31) could not be accessed, so a later package could in principle reconcile the European-scenario and regional-column differences; the audit relies on the December 2017 WIR computer-codes archive, which is a slightly earlier vintage than the published figures. R/gpinter was not run; global merges use the adjudicator's own interpolation, validated against the authors' gpinter output. Country distributions were not rebuilt from tax or survey microdata, and the true 1980-84 MENA incomes are not certified (only shown to be what the authors' imported national accounts, WDI and the current WID imply). The adult-population correction uses current World Bank/WPP age structures rather than WPP 2017. The country-means test may double count part of between-country dispersion. The projection alternatives (no clipping, donor growth profiles) are diagnostics, not preferred forecasts. Current-WID comparisons are not like-for-like (different PPPs, data and methods). Sandefur (2018) was read only via the critique corpus; Auditor A's poverty-headcount and PSZ comparisons were not re-run.