placestats

Married by 18 vs. Slum share of urban population

Fades after adjusting for income

Across 133 countries, Married by 18 and Slum share of urban population rise and fall together at r = +0.62 (on a scale from −1 to +1, where 0 means no link). Comparing only countries with similar income (GDP per person) shrinks it to +0.35, which could easily be chance (q = 0.20, 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 married by 18, 6.9% to 27.9% of women aged 20-24, slum share of urban population is worse by 23% of urban population at the top of that range than the bottom. Comparing only countries with similar national income, the gap is 11.7% of urban population.

Link before adjusting (r)+0.619p = 2.1e-15 · 133 countries
After adjusting for national income+0.348p = 4.4e-5 · likely range [+0.19, +0.49]
p, allowing for regions0.061standard error 0.144 · 6 regions
Check for luck (q)0.203across 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.

Married by 18 · % of women aged 20-24link with income -0.60 · moderate
Slum share of urban population · % of urban populationlink with income -0.78 · high

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

Every country as a dot

Married by 18 · % of women aged 20-24 →Slum share of urban population · % of urban population →0%76.3%0%92.5%Afghanistan: 28.7% of women aged 20-24, 71.6% of urban populationAngola: 23.1% of women aged 20-24, 62.7% of urban populationAlbania: 11.8% of women aged 20-24, 2.7% of urban populationArgentina: 15.5% of women aged 20-24, 14.5% of urban populationArmenia: 5.3% of women aged 20-24, 8.39% of urban populationAzerbaijan: 15% of women aged 20-24, 26.9% of urban populationBurundi: 19% of women aged 20-24, 36.8% of urban populationBelgium: 0.1% of women aged 20-24, 0% of urban populationBenin: 27.5% of women aged 20-24, 64% of urban populationBurkina Faso: 38.2% of women aged 20-24, 87.9% of urban populationBangladesh: 47.2% of women aged 20-24, 51.5% of urban populationBosnia and Herzegovina: 3.5% of women aged 20-24, 0.313% of urban populationBelarus: 4.7% of women aged 20-24, 0.004% of urban populationBelize: 33.5% of women aged 20-24, 15.7% of urban populationBolivia: 14.5% of women aged 20-24, 46.6% of urban populationBhutan: 9% of women aged 20-24, 44.7% of urban populationCentral African Republic: 61% of women aged 20-24, 68.9% of urban populationChile: 0% of women aged 20-24, 7.32% of urban populationChina: 2.8% of women aged 20-24, 26.3% of urban populationCote d'Ivoire: 25.8% of women aged 20-24, 48.3% of urban populationCameroon: 29.8% of women aged 20-24, 32.7% of urban populationCongo, Dem. Rep.: 29.9% of women aged 20-24, 78.4% of urban populationCongo, Rep.: 27.3% of women aged 20-24, 75.3% of urban populationColombia: 23.4% of women aged 20-24, 9.7% of urban populationComoros: 20.7% of women aged 20-24, 48.5% of urban populationCabo Verde: 8.4% of women aged 20-24, 46.4% of urban populationCosta Rica: 17.1% of women aged 20-24, 3.55% of urban populationDjibouti: 6.5% of women aged 20-24, 48.7% of urban populationDenmark: 0.7% of women aged 20-24, 0% of urban populationDominican Republic: 31.5% of women aged 20-24, 11.2% of urban populationAlgeria: 3.8% of women aged 20-24, 13.2% of urban populationEcuador: 22.2% of women aged 20-24, 57.8% of urban populationEgypt, Arab Rep.: 15.8% of women aged 20-24, 3.84% of urban populationEthiopia: 40.3% of women aged 20-24, 64.3% of urban populationFinland: 0.1% of women aged 20-24, 0% of urban populationFiji: 4% of women aged 20-24, 9.4% of urban populationGabon: 13.3% of women aged 20-24, 38.8% of urban populationUnited Kingdom: 0% of women aged 20-24, 0.163% of urban populationGeorgia: 9.4% of women aged 20-24, 7.08% of urban populationGhana: 16.1% of women aged 20-24, 33.5% of urban populationGuinea: 46.5% of women aged 20-24, 44% of urban populationGambia, The: 23.1% of women aged 20-24, 37.1% of urban populationGuinea-Bissau: 25.7% of women aged 20-24, 59% of urban populationEquatorial Guinea: 29.5% of women aged 20-24, 64.7% of urban populationGuatemala: 29.5% of women aged 20-24, 37.6% of urban populationGuyana: 32.3% of women aged 20-24, 11.3% of urban populationHonduras: 34% of women aged 20-24, 31.5% of urban populationHaiti: 14.9% of women aged 20-24, 51.1% of urban populationIndonesia: 16.3% of women aged 20-24, 19.4% of urban populationIndia: 22.3% of women aged 20-24, 5.41% of urban populationIran, Islamic Rep.: 16.7% of women aged 20-24, 44.7% of urban populationIraq: 27.9% of women aged 20-24, 49.3% of urban populationJamaica: 26.9% of women aged 20-24, 0.883% of urban populationJordan: 9.9% of women aged 20-24, 23.4% of urban populationKazakhstan: 6.1% of women aged 20-24, 0.794% of urban populationKenya: 12.5% of women aged 20-24, 40.5% of urban populationKyrgyz Republic: 9.2% of women aged 20-24, 2.44% of urban populationCambodia: 17.9% of women aged 20-24, 42.3% of urban populationKiribati: 18.4% of women aged 20-24, 5.93% of urban populationLao PDR: 30.5% of women aged 20-24, 54.8% of urban populationLebanon: 6% of women aged 20-24, 4.53% of urban populationLiberia: 24.9% of women aged 20-24, 60.5% of urban populationLibya: 4.1% of women aged 20-24, 16.6% of urban populationSt. Lucia: 24% of women aged 20-24, 0.441% of urban populationSri Lanka: 9.8% of women aged 20-24, 44.7% of urban populationLesotho: 13.4% of women aged 20-24, 25.6% of urban populationLithuania: 0.2% of women aged 20-24, 0.509% of urban populationMorocco: 13.7% of women aged 20-24, 10.9% of urban populationMoldova: 12.2% of women aged 20-24, 6.5% of urban populationMadagascar: 38.8% of women aged 20-24, 65.7% of urban populationMaldives: 2.2% of women aged 20-24, 34.8% of urban populationMexico: 18.2% of women aged 20-24, 17.6% of urban populationNorth Macedonia: 7.5% of women aged 20-24, 0.278% of urban populationMali: 48.5% of women aged 20-24, 92.5% of urban populationMyanmar: 16% of women aged 20-24, 58.3% of urban populationMontenegro: 5.8% of women aged 20-24, 8.77% of urban populationMongolia: 8.1% of women aged 20-24, 17.9% of urban populationMozambique: 48.4% of women aged 20-24, 55% of urban populationMauritania: 36.6% of women aged 20-24, 58.6% of urban populationMalawi: 38.7% of women aged 20-24, 38% of urban populationNamibia: 6.9% of women aged 20-24, 41.4% of urban populationNiger: 76.3% of women aged 20-24, 70.4% of urban populationNigeria: 33.4% of women aged 20-24, 48.5% of urban populationNicaragua: 35.2% of women aged 20-24, 5.52% of urban populationNorway: 0% of women aged 20-24, 0% of urban populationNepal: 34.9% of women aged 20-24, 40.1% of urban populationNaoero: 18.2% of women aged 20-24, 0.597% of urban populationOman: 4% of women aged 20-24, 0% of urban populationPakistan: 18.3% of women aged 20-24, 56% of urban populationPanama: 26.4% of women aged 20-24, 16.3% of urban populationPeru: 17.9% of women aged 20-24, 45.1% of urban populationPhilippines: 9.4% of women aged 20-24, 35.9% of urban populationPapua New Guinea: 27.3% of women aged 20-24, 22.3% of urban populationParaguay: 21.6% of women aged 20-24, 15.1% of urban populationWest Bank and Gaza: 13.4% of women aged 20-24, 19.5% of urban populationQatar: 1.7% of women aged 20-24, 0% of urban populationRomania: 6.9% of women aged 20-24, 2.52% of urban populationRussian Federation: 6.2% of women aged 20-24, 2.62% of urban populationRwanda: 5.5% of women aged 20-24, 38.3% of urban populationSaudi Arabia: 3.4% of women aged 20-24, 0.55% of urban populationSudan: 34.2% of women aged 20-24, 73.7% of urban populationSenegal: 30.2% of women aged 20-24, 46.4% of urban populationSingapore: 0.1% of women aged 20-24, 0% of urban populationSolomon Islands: 21.3% of women aged 20-24, 1.95% of urban populationSierra Leone: 29.6% of women aged 20-24, 49.3% of urban populationEl Salvador: 19.7% of women aged 20-24, 16.5% of urban populationSerbia: 5.5% of women aged 20-24, 1.42% of urban populationSao Tome and Principe: 28% of women aged 20-24, 82.4% of urban populationSuriname: 36% of women aged 20-24, 15.8% of urban populationEswatini: 1.9% of women aged 20-24, 17% of urban populationTurks and Caicos Islands: 23.3% of women aged 20-24, 0.631% of urban populationChad: 60.6% of women aged 20-24, 82% of urban populationTogo: 24.8% of women aged 20-24, 38.5% of urban populationThailand: 17% of women aged 20-24, 2% of urban populationTajikistan: 8.8% of women aged 20-24, 0.05% of urban populationTurkmenistan: 6.1% of women aged 20-24, 8.38% of urban populationTimor-Leste: 14.9% of women aged 20-24, 33.9% of urban populationTonga: 10.1% of women aged 20-24, 0.308% of urban populationTrinidad and Tobago: 4.2% of women aged 20-24, 8.63% of urban populationTunisia: 2.4% of women aged 20-24, 7.64% of urban populationTurkiye: 14.7% of women aged 20-24, 14.1% of urban populationTuvalu: 1.8% of women aged 20-24, 50.9% of urban populationTanzania: 29.1% of women aged 20-24, 70.1% of urban populationUganda: 34% of women aged 20-24, 52.7% of urban populationUkraine: 9.1% of women aged 20-24, 1.1% of urban populationUruguay: 24.6% of women aged 20-24, 1.3% of urban populationUzbekistan: 3.4% of women aged 20-24, 7.1% of urban populationViet Nam: 14.6% of women aged 20-24, 32.5% of urban populationVanuatu: 20.9% of women aged 20-24, 3.06% of urban populationSamoa: 7.4% of women aged 20-24, 34.6% of urban populationSouth Africa: 3.6% of women aged 20-24, 24.2% of urban populationZambia: 23.9% of women aged 20-24, 48.3% of urban populationZimbabwe: 33.7% of women aged 20-24, 54.9% of urban populationBELDJIGBRMLINERNICNORSTPSURTCDTUV

best-fit line line after adjusting

Four ways to measure the link

MethodrpCountries
Standard (Pearson), not adjusted+0.6192.1e-15133
By rank (Spearman), not adjusted+0.6144.0e-15133
Standard (Pearson), adjusted for national income+0.3484.4e-5133
By rank (Spearman), adjusted for national income+0.3358.7e-5133

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 133 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: +0.271 (a minus sign means it grew).

How solid is it?

Leaving out one country at a time, r ranges from +0.327 (without TCD) to +0.368 (without NIC). 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: TCD (-0.021).

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 & Pacific20-0.05
Europe & Central Asia25+0.64
Latin America & Caribbean24-0.17
Middle East, North Africa, Afghanistan & Pakistan16+0.59
Sub-Saharan Africa42+0.56

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 third45+0.50
Middle third44+0.34
Richest third44+0.11

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
Christians75+0.27
Muslims42+0.60

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
France24+0.44
Never a European colony19+0.61
Spain19-0.01
United Kingdom41+0.16

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 = +0.329 after dropping 3 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.

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Over time, within countries

Everything above compares countries with each other at one moment. This section compares each country only with itself over 0years. So a link here can’t come from anything about a country that stays the same, such as its history, geography, institutions or culture.

Not enough history inside each country to look at this over time. That needs countries measured for several years in a row, and at least one of these measures is measured too rarely.

The data


% of women aged 20-24
% of urban population		Years
Niger NER76.3%70.4%2012, 2022
Central African Republic CAF61%68.9%2019, 2022
Chad TCD60.6%82%2019, 2022
Mali MLI48.5%92.5%2024, 2022
Mozambique MOZ48.4%55%2023, 2022
Bangladesh BGD47.2%51.5%2025, 2022
Guinea GIN46.5%44%2018, 2022
Ethiopia ETH40.3%64.3%2016, 2022
Madagascar MDG38.8%65.7%2021, 2022
Malawi MWI38.7%38%2024, 2022
Burkina Faso BFA38.2%87.9%2021, 2022
Mauritania MRT36.6%58.6%2021, 2022
Suriname SUR36%15.8%2018, 2022
Nicaragua NIC35.2%5.52%2012, 2020
Nepal NPL34.9%40.1%2022

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

Sources

Married by 18

Women who were first married by age 18 (% of women ages 20-24)

UNICEF · CC BY 4.0 · updated quarterly

From household surveys, mostly in lower-income countries, and only in years a survey ran. No year reaches sixty countries, so the latest value used is up to a decade old for some. Rich countries rarely report it at all, which shapes any link with income.

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 2010–2025. 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 6 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 Married by 18 and Slum share of urban population

This page shows that two measures go together. It does not show that Married by 18 changes Slum share of urban population, or the reverse. These figures also describe countries, not individual people. See the ecological fallacy.

More links with Married by 18 or Slum share of urban population