placestats

Fertility rate vs. Slum share of urban population

Fades after adjusting for income

Across 184 countries, Fertility rate and Slum share of urban population rise and fall together at r = +0.76 (on a scale from −1 to +1, where 0 means no link). Comparing only countries with similar income (GDP per person) shrinks it to +0.38, which could easily be chance (q = 0.053, allowing for the many pairs tested, and allowing for countries in the same region being alike). So the first figure mostly shows richer countries differing from poorer ones, not a link between these two things. Caution: direction is not consistent across regions.

Comparing countries across the middle half of fertility rate, 1.46 to 3.21 births per woman, slum share of urban population is worse by 27.1% of urban population at the top of that range than the bottom. Comparing only countries with similar national income, the gap is 16.4% of urban population.

Link before adjusting (r)+0.759p = 1.1e-35 · 184 countries
After adjusting for national income+0.383p = 8.7e-8 · likely range [+0.25, +0.50]
p, allowing for regions0.005standard error 0.090 · 7 regions
Check for luck (q)0.053across 12,497 pairs

How to read these.r runs from −1 (one goes up as the other goes down) to +1 (they rise together), and 0 means no link. Adjusting for national income means comparing countries with the same GDP per person, so differences in wealth can’t explain the link. Income is used in percentage terms, since an extra $1,000 means more to a poor country than to a rich one. p is how likely a link this strong would be if there were really none. Below 0.05 means it is unlikely to be chance. Very small values are written in short form: 1.1e-32 means a decimal point followed by 31 zeros and then 11, so very close to zero. The likely range is where the true figure probably lies, and a range that crosses zero means the link could easily be chance. Countries in the same region tend to resemble each other, so the third figure allows for that, which gives a fairer p. The standard error is the typical size of the error in r. Finally, testing this many pairs means some will look strong by luck alone. A q below 0.05 means this link is unlikely to be one of those.

Fertility rate · births per womanlink with income -0.81 · proxy
Slum share of urban population · % of urban populationlink with income -0.78 · high

Both of these rise and fall closely with national income, so a strong link between them before adjusting was close to certain. Read the adjusted figure, not the first one.

“Link with income” is how closely each measure tracks GDP per person across countries, from −1 to +1.

Every country as a dot

Fertility rate · births per woman →Slum share of urban population · % of urban population →0.7486.030%92.5%Aruba: 1.61 births per woman, 0% of urban populationAfghanistan: 4.76 births per woman, 71.6% of urban populationAngola: 5.05 births per woman, 62.7% of urban populationAlbania: 1.34 births per woman, 2.7% of urban populationAndorra: 1.09 births per woman, 0% of urban populationUnited Arab Emirates: 1.21 births per woman, 0.113% of urban populationArgentina: 1.5 births per woman, 14.5% of urban populationArmenia: 1.7 births per woman, 8.39% of urban populationAntigua and Barbuda: 1.58 births per woman, 2.65% of urban populationAustralia: 1.48 births per woman, 0.035% of urban populationAustria: 1.31 births per woman, 0.0466% of urban populationAzerbaijan: 1.43 births per woman, 26.9% of urban populationBurundi: 4.79 births per woman, 36.8% of urban populationBelgium: 1.44 births per woman, 0% of urban populationBenin: 4.48 births per woman, 64% of urban populationBurkina Faso: 4.11 births per woman, 87.9% of urban populationBangladesh: 2.14 births per woman, 51.5% of urban populationBulgaria: 1.72 births per woman, 0.197% of urban populationBahrain: 1.8 births per woman, 0% of urban populationBosnia and Herzegovina: 1.49 births per woman, 0.313% of urban populationBelarus: 1.22 births per woman, 0.004% of urban populationBelize: 2.02 births per woman, 15.7% of urban populationBermuda: 1.41 births per woman, 0.0776% of urban populationBolivia: 2.52 births per woman, 46.6% of urban populationBrazil: 1.61 births per woman, 14.9% of urban populationBrunei Darussalam: 1.73 births per woman, 21.6% of urban populationBhutan: 1.45 births per woman, 44.7% of urban populationBotswana: 2.7 births per woman, 39.6% of urban populationCentral African Republic: 5.95 births per woman, 68.9% of urban populationCanada: 1.25 births per woman, 1.1% of urban populationSwitzerland: 1.29 births per woman, 0% of urban populationChile: 1.14 births per woman, 7.32% of urban populationChina: 1.01 births per woman, 26.3% of urban populationCote d'Ivoire: 4.23 births per woman, 48.3% of urban populationCameroon: 4.26 births per woman, 32.7% of urban populationCongo, Dem. Rep.: 5.98 births per woman, 78.4% of urban populationCongo, Rep.: 4.11 births per woman, 75.3% of urban populationColombia: 1.63 births per woman, 9.7% of urban populationComoros: 3.82 births per woman, 48.5% of urban populationCabo Verde: 1.51 births per woman, 46.4% of urban populationCosta Rica: 1.32 births per woman, 3.55% of urban populationCayman Islands: 1.52 births per woman, 5.48% of urban populationCyprus: 1.38 births per woman, 0.272% of urban populationCzechia: 1.36 births per woman, 0.0273% of urban populationGermany: 1.36 births per woman, 0% of urban populationDjibouti: 2.62 births per woman, 48.7% of urban populationDenmark: 1.47 births per woman, 0% of urban populationDominican Republic: 2.22 births per woman, 11.2% of urban populationAlgeria: 2.72 births per woman, 13.2% of urban populationEcuador: 1.81 births per woman, 57.8% of urban populationEgypt, Arab Rep.: 2.73 births per woman, 3.84% of urban populationSpain: 1.1 births per woman, 0.046% of urban populationEstonia: 1.18 births per woman, 0.345% of urban populationEthiopia: 3.91 births per woman, 64.3% of urban populationFinland: 1.25 births per woman, 0% of urban populationFiji: 2.27 births per woman, 9.4% of urban populationFrance: 1.61 births per woman, 0% of urban populationGabon: 3.59 births per woman, 38.8% of urban populationUnited Kingdom: 1.55 births per woman, 0.163% of urban populationGeorgia: 1.8 births per woman, 7.08% of urban populationGhana: 3.34 births per woman, 33.5% of urban populationGuinea: 4.13 births per woman, 44% of urban populationGambia, The: 3.91 births per woman, 37.1% of urban populationGuinea-Bissau: 3.76 births per woman, 59% of urban populationEquatorial Guinea: 4.12 births per woman, 64.7% of urban populationGreece: 1.24 births per woman, 0.05% of urban populationGuatemala: 2.29 births per woman, 37.6% of urban populationGuyana: 2.4 births per woman, 11.3% of urban populationHonduras: 2.48 births per woman, 31.5% of urban populationCroatia: 1.46 births per woman, 0.527% of urban populationHaiti: 2.63 births per woman, 51.1% of urban populationHungary: 1.41 births per woman, 7.2% of urban populationIndonesia: 2.12 births per woman, 19.4% of urban populationIndia: 1.96 births per woman, 5.41% of urban populationIreland: 1.47 births per woman, 8.5% of urban populationIran, Islamic Rep.: 1.68 births per woman, 44.7% of urban populationIraq: 3.22 births per woman, 49.3% of urban populationIceland: 1.56 births per woman, 0% of urban populationItaly: 1.18 births per woman, 0.02% of urban populationJamaica: 1.35 births per woman, 0.883% of urban populationJordan: 2.6 births per woman, 23.4% of urban populationJapan: 1.15 births per woman, 2% of urban populationKazakhstan: 2.98 births per woman, 0.794% of urban populationKenya: 3.17 births per woman, 40.5% of urban populationKyrgyz Republic: 2.6 births per woman, 2.44% of urban populationCambodia: 2.55 births per woman, 42.3% of urban populationKiribati: 3.12 births per woman, 5.93% of urban populationKorea, Rep.: 0.748 births per woman, 4.5% of urban populationKuwait: 1.56 births per woman, 0% of urban populationLao PDR: 2.4 births per woman, 54.8% of urban populationLebanon: 2.23 births per woman, 4.53% of urban populationLiberia: 3.86 births per woman, 60.5% of urban populationLibya: 2.3 births per woman, 16.6% of urban populationSt. Lucia: 1.39 births per woman, 0.441% of urban populationSri Lanka: 1.95 births per woman, 44.7% of urban populationLesotho: 2.66 births per woman, 25.6% of urban populationLithuania: 1.11 births per woman, 0.509% of urban populationLuxembourg: 1.25 births per woman, 0.0173% of urban populationLatvia: 1.24 births per woman, 0.593% of urban populationMorocco: 2.21 births per woman, 10.9% of urban populationMoldova: 1.73 births per woman, 6.5% of urban populationMadagascar: 3.91 births per woman, 65.7% of urban populationMaldives: 1.56 births per woman, 34.8% of urban populationMexico: 1.89 births per woman, 17.6% of urban populationMarshall Islands: 2.86 births per woman, 2.38% of urban populationNorth Macedonia: 1.4 births per woman, 0.278% of urban populationMali: 5.51 births per woman, 92.5% of urban populationMalta: 1.01 births per woman, 0.0375% of urban populationMyanmar: 2.1 births per woman, 58.3% of urban populationMontenegro: 1.8 births per woman, 8.77% of urban populationMongolia: 2.5 births per woman, 17.9% of urban populationMozambique: 4.69 births per woman, 55% of urban populationMauritania: 4.63 births per woman, 58.6% of urban populationMauritius: 1.44 births per woman, 48.7% of urban populationMalawi: 3.59 births per woman, 38% of urban populationMalaysia: 1.54 births per woman, 0.2% of urban populationNamibia: 3.21 births per woman, 41.4% of urban populationNiger: 5.93 births per woman, 70.4% of urban populationNigeria: 4.38 births per woman, 48.5% of urban populationNicaragua: 2.21 births per woman, 5.52% of urban populationNetherlands: 1.43 births per woman, 0% of urban populationNorway: 1.45 births per woman, 0% of urban populationNepal: 1.96 births per woman, 40.1% of urban populationNaoero: 3.29 births per woman, 0.597% of urban populationNew Zealand: 1.57 births per woman, 0% of urban populationOman: 2.51 births per woman, 0% of urban populationPakistan: 3.55 births per woman, 56% of urban populationPanama: 2.11 births per woman, 16.3% of urban populationPeru: 1.97 births per woman, 45.1% of urban populationPhilippines: 1.89 births per woman, 35.9% of urban populationPalau: 1.88 births per woman, 0.618% of urban populationPapua New Guinea: 3.07 births per woman, 22.3% of urban populationPoland: 1.14 births per woman, 4.22% of urban populationPortugal: 1.41 births per woman, 0.059% of urban populationParaguay: 2.42 births per woman, 15.1% of urban populationWest Bank and Gaza: 3.25 births per woman, 19.5% of urban populationQatar: 1.72 births per woman, 0% of urban populationRomania: 1.39 births per woman, 2.52% of urban populationRussian Federation: 1.42 births per woman, 2.62% of urban populationRwanda: 3.65 births per woman, 38.3% of urban populationSaudi Arabia: 2.31 births per woman, 0.55% of urban populationSudan: 4.26 births per woman, 73.7% of urban populationSenegal: 3.77 births per woman, 46.4% of urban populationSingapore: 0.97 births per woman, 0% of urban populationSolomon Islands: 3.51 births per woman, 1.95% of urban populationSierra Leone: 3.7 births per woman, 49.3% of urban populationEl Salvador: 1.77 births per woman, 16.5% of urban populationSomalia, Fed. Rep.: 6.01 births per woman, 48.7% of urban populationSerbia: 1.64 births per woman, 1.42% of urban populationSao Tome and Principe: 3.6 births per woman, 82.4% of urban populationSuriname: 2.23 births per woman, 15.8% of urban populationSlovak Republic: 1.46 births per woman, 0.066% of urban populationSlovenia: 1.52 births per woman, 0.527% of urban populationSweden: 1.43 births per woman, 0.336% of urban populationEswatini: 2.72 births per woman, 17% of urban populationSint Maarten (Dutch part): 1.44 births per woman, 2.89% of urban populationSeychelles: 1.85 births per woman, 48.7% of urban populationSyrian Arab Republic: 2.7 births per woman, 41.1% of urban populationTurks and Caicos Islands: 1.45 births per woman, 0.631% of urban populationChad: 6.03 births per woman, 82% of urban populationTogo: 4.12 births per woman, 38.5% of urban populationThailand: 1.2 births per woman, 2% of urban populationTajikistan: 3.04 births per woman, 0.05% of urban populationTurkmenistan: 2.66 births per woman, 8.38% of urban populationTimor-Leste: 2.63 births per woman, 33.9% of urban populationTonga: 3.1 births per woman, 0.308% of urban populationTrinidad and Tobago: 1.54 births per woman, 8.63% of urban populationTunisia: 1.82 births per woman, 7.64% of urban populationTurkiye: 1.48 births per woman, 14.1% of urban populationTuvalu: 3.17 births per woman, 50.9% of urban populationTanzania: 4.54 births per woman, 70.1% of urban populationUganda: 4.17 births per woman, 52.7% of urban populationUkraine: 0.988 births per woman, 1.1% of urban populationUruguay: 1.4 births per woman, 1.3% of urban populationUnited States: 1.63 births per woman, 0.0932% of urban populationUzbekistan: 3.49 births per woman, 7.1% of urban populationSt. Vincent and the Grenadines: 1.76 births per woman, 2.76% of urban populationVirgin Islands (U.S.): 1.97 births per woman, 1.1% of urban populationViet Nam: 1.9 births per woman, 32.5% of urban populationVanuatu: 3.57 births per woman, 3.06% of urban populationSamoa: 3.8 births per woman, 34.6% of urban populationSouth Africa: 2.21 births per woman, 24.2% of urban populationZambia: 4.04 births per woman, 48.3% of urban populationZimbabwe: 3.67 births per woman, 54.9% of urban populationCODCPVECUKORMLIMLTMUSSGPSLBSOMTCDVUT

best-fit line line after adjusting

Four ways to measure the link

MethodrpCountries
Standard (Pearson), not adjusted+0.7591.1e-35184
By rank (Spearman), not adjusted+0.7271.8e-31184
Standard (Pearson), adjusted for national income+0.3838.7e-8184
By rank (Spearman), adjusted for national income+0.2220.002184

The rank version uses only each country’s place in line, from lowest to highest, so a few extreme countries count for less. The adjusted and unadjusted versions use the same 184 countries: those that report both measures and GDP per person. So the gap between them comes from the adjustment, not from a change in which countries are counted. Drop in the size of r after adjusting: +0.375 (a minus sign means it grew).

How solid is it?

Leaving out one country at a time, r ranges from +0.360 (without MLI) to +0.400 (without ECU). The bar above shows that range on a scale from −1 to +1, with the solid line at the full result. The single country that moves r most: MLI (-0.023).

Fragile: this link may not hold up.
  • direction is not consistent across regions

Within each region

Countries are not separate, unrelated cases, and neighbors share a lot. A link that holds inside each region is far more believable than one that shows up only when comparing regions.

nr
East Asia & Pacific28-0.25
Europe & Central Asia49+0.02
Latin America & Caribbean31+0.44
Middle East, North Africa, Afghanistan & Pakistan21+0.31
Sub-Saharan Africa46+0.48

By income third

If the link shows up only in the richest third of countries, it is a feature of rich countries, not a general pattern.

nr
Poorest third62+0.48
Middle third61+0.22
Richest third61+0.19

By largest religious group

Countries grouped by a label they share, such as main religion, rather than by a number. Groups of fewer than twelve countries are not shown. These groups differ in income, region and history all at once. So a gap between them is a place to start asking questions, not an answer.

nr
Christians106+0.52
Muslims49+0.36

By last european coloniser

Countries grouped by a label they share, such as main religion, rather than by a number. Groups of fewer than twelve countries are not shown. These groups differ in income, region and history all at once. So a gap between them is a place to start asking questions, not an answer.

nr
France25+0.46
Never a European colony21-0.12
Spain19+0.54
United Kingdom57+0.25

Without outliers (countries far outside the middle half of countries on either measure, by more than one and a half times the width of that middle half): r = +0.366 after dropping 5 countries.

Two series, one country

Both measures over the years for one country you pick. The two charts are stacked so they share only the years along the bottom.

Loading…

Over time, within countries

Everything above compares countries with each other at one moment. This section compares each country only with itself over 23years. So a link here can’t come from anything about a country that stays the same, such as its history, geography, institutions or culture.

The link shows up within countries over time (r = +0.147) but mostly disappears in year-to-year changes (r = —). That points to slow trends particular to each country, not the two measures moving together from year to year.

Across countries (adjusted)+0.383for comparison
Within countries+0.394each country vs itself
…and vs the same year elsewhere+0.147q = 0.044 · 174 countries
Year-on-year changes—q = —
Read with care.
  • Almost all of this indicator's variation is between countries, not within them, so the within-country estimate rests on a small part of the data.
  • Much of the within-country association disappears once shared global year effects are removed, which points to a common worldwide trend rather than a country-level relationship.

1,988 country-years (one country in one year), 174 countries, 2000–2022, about 11 years each on average. Share of the variation that happens within countries over time: 5% for Fertility rate, 8% for Slum share of urban population. The margins of error allow for each country appearing many times, and for each year’s value being close to the year before.

Year-to-year changes are a cautious test, not a final answer. Looking only at changes from one year to the next removes each country’s own trends. But it also makes measurement mistakes louder, which pulls the results toward zero. A near-zero result here is weak evidence of no link, not proof.

With one measure years behind the other

0.30−0.3-100+10years Slum share of urban population trails Fertility rate →lag -10: r = 0.092 (n = 1,309)lag -9: r = 0.098 (n = 1,309)lag -8: r = 0.102 (n = 1,477)lag -7: r = 0.103 (n = 1,477)lag -6: r = 0.114 (n = 1,647)lag -5: r = 0.118 (n = 1,647)lag -4: r = 0.135 (n = 1,810)lag -3: r = 0.139 (n = 1,810)lag -2: r = 0.137 (n = 1,988)lag -1: r = 0.142 (n = 1,988)lag +0: r = 0.147 (n = 1,988)lag +1: r = 0.154 (n = 1,988)lag +2: r = 0.162 (n = 1,988)lag +3: r = 0.172 (n = 1,988)lag +4: r = 0.185 (n = 1,988)lag +5: r = 0.199 (n = 1,988)lag +6: r = 0.207 (n = 1,988)lag +7: r = 0.216 (n = 1,988)lag +8: r = 0.226 (n = 1,988)lag +9: r = 0.232 (n = 1,988)lag +10: r = 0.236 (n = 1,988)

Same year (lag 0): +0.147. A peak away from zero does not show which comes first. These series change slowly — this year’s value is close to last year’s. That makes the curve smooth and nearly symmetric, whatever produced the data. Even a sharp peak at one lag (a gap of some years) would not prove that one measure changes the other.

This curve peaks at the edge of the window (lag +10), so it is still drifting where the search stops. That pattern usually reflects a slow trend left over in the data, not a link with real timing. The peak value should not be read as the “true” link at the right lag.

The data


births per woman
% of urban population		Years
Chad TCD6.0382%2024, 2022
Somalia, Fed. Rep. SOM6.0148.7%2024, 2022
Congo, Dem. Rep. COD5.9878.4%2024, 2022
Central African Republic CAF5.9568.9%2024, 2022
Niger NER5.9370.4%2024, 2022
Mali MLI5.5192.5%2024, 2022
Angola AGO5.0562.7%2024, 2022
Burundi BDI4.7936.8%2024, 2022
Afghanistan AFG4.7671.6%2024, 2022
Mozambique MOZ4.6955%2024, 2022
Mauritania MRT4.6358.6%2024, 2022
Tanzania TZA4.5470.1%2024, 2022
Benin BEN4.4864%2024, 2022
Nigeria NGA4.3848.5%2024, 2022
Sudan SDN4.2673.7%2024, 2022

World Bank, World Development Indicators
World Bank, World Development Indicators

Sources

Fertility rate

Fertility rate, total (births per woman)

World Bank · CC BY 4.0 · updated quarterly

Slum share of urban population

Population living in slums (% of urban population)

UN-Habitat · CC BY 4.0 · updated quarterly

How this was computed

Data used: most recent value in 2010-2025; values come from 2012–2024. To adjust for income, each measure is first predicted from GDP per person (in percentage terms, on a log scale) with a straight-line fit. Only what is left over is then compared. This is called a partial correlation. The line is drawn the standard way (ordinary least squares), which picks the line that comes closest to all the countries at once. The error margins allow for countries in the same region resembling each other, using 7 World Bank regions. The q-value corrects for testing all 12,497 pairs at once, using the Benjamini–Hochberg method. Underlying data last updated DYB 2024. How the country data works · explore Fertility rate and Slum share of urban population

This page shows that two measures go together. It does not show that Fertility rate changes Slum share of urban population, or the reverse. These figures also describe countries, not individual people. See the ecological fallacy.

More links with Fertility rate or Slum share of urban population