placestats

Birth registration vs. Married by 18

Fades after adjusting for income

Across 128 countries, Birth registration and Married by 18 rise and fall together at r = -0.52 (on a scale from −1 to +1, where 0 means no link). Comparing only countries with similar income (GDP per person) shrinks it to -0.23, which could easily be chance (q = 0.17, 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.

Comparing countries across the middle half of married by 18, 7.47% to 28.8% of women aged 20-24, birth registration is worse by 18% of children under 5 at the top of that range than the bottom. Comparing only countries with similar national income, the gap is 7.87% of children under 5.

Link before adjusting (r)-0.523p = 2.5e-10 · 128 countries
After adjusting for national income-0.232p = 0.009 · likely range [-0.39, -0.06]
p, allowing for regions0.009standard error 0.056 · 6 regions
Check for luck (q)0.168across 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.

Birth registration · % of children under 5link with income +0.87 · proxy
Married by 18 · % of women aged 20-24link with income -0.60 · moderate

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

Every country as a dot

Birth registration · % of children under 5 →Married by 18 · % of women aged 20-24 →2.7%100%0%76.3%Afghanistan: 42.3% of children under 5, 28.7% of women aged 20-24Angola: 25% of children under 5, 23.1% of women aged 20-24Albania: 98.4% of children under 5, 11.8% of women aged 20-24Argentina: 99.7% of children under 5, 15.5% of women aged 20-24Armenia: 99.3% of children under 5, 5.3% of women aged 20-24Burundi: 83.5% of children under 5, 19% of women aged 20-24Belgium: 100% of children under 5, 0.1% of women aged 20-24Benin: 85.6% of children under 5, 27.5% of women aged 20-24Burkina Faso: 76.9% of children under 5, 38.2% of women aged 20-24Bangladesh: 56% of children under 5, 47.2% of women aged 20-24Belarus: 100% of children under 5, 4.7% of women aged 20-24Belize: 95.7% of children under 5, 33.5% of women aged 20-24Bolivia: 91.9% of children under 5, 14.5% of women aged 20-24Barbados: 98.7% of children under 5, 29.2% of women aged 20-24Bhutan: 99.9% of children under 5, 9% of women aged 20-24Central African Republic: 44.8% of children under 5, 61% of women aged 20-24Chile: 99.4% of children under 5, 0% of women aged 20-24Cote d'Ivoire: 71.7% of children under 5, 25.8% of women aged 20-24Cameroon: 61.9% of children under 5, 29.8% of women aged 20-24Congo, Dem. Rep.: 40.1% of children under 5, 29.9% of women aged 20-24Congo, Rep.: 95.9% of children under 5, 27.3% of women aged 20-24Colombia: 96.8% of children under 5, 23.4% of women aged 20-24Comoros: 87.3% of children under 5, 20.7% of women aged 20-24Cabo Verde: 91.4% of children under 5, 8.4% of women aged 20-24Costa Rica: 99.6% of children under 5, 17.1% of women aged 20-24Denmark: 100% of children under 5, 0.7% of women aged 20-24Dominican Republic: 92.2% of children under 5, 31.5% of women aged 20-24Algeria: 99.6% of children under 5, 3.8% of women aged 20-24Ecuador: 87.2% of children under 5, 22.2% of women aged 20-24Egypt, Arab Rep.: 99.4% of children under 5, 15.8% of women aged 20-24Ethiopia: 2.7% of children under 5, 40.3% of women aged 20-24Finland: 100% of children under 5, 0.1% of women aged 20-24Fiji: 86.6% of children under 5, 4% of women aged 20-24Gabon: 89.6% of children under 5, 13.3% of women aged 20-24United Kingdom: 100% of children under 5, 0% of women aged 20-24Georgia: 98.5% of children under 5, 9.4% of women aged 20-24Ghana: 70.6% of children under 5, 16.1% of women aged 20-24Guinea: 62% of children under 5, 46.5% of women aged 20-24Gambia, The: 59% of children under 5, 23.1% of women aged 20-24Guinea-Bissau: 46% of children under 5, 25.7% of women aged 20-24Equatorial Guinea: 53.5% of children under 5, 29.5% of women aged 20-24Guatemala: 96.4% of children under 5, 29.5% of women aged 20-24Guyana: 98.1% of children under 5, 32.3% of women aged 20-24Honduras: 97% of children under 5, 34% of women aged 20-24Haiti: 84.8% of children under 5, 14.9% of women aged 20-24Indonesia: 77% of children under 5, 16.3% of women aged 20-24India: 89.1% of children under 5, 22.3% of women aged 20-24Iran, Islamic Rep.: 98.6% of children under 5, 16.7% of women aged 20-24Iraq: 98.8% of children under 5, 27.9% of women aged 20-24Israel: 100% of children under 5, 0.8% of women aged 20-24Jamaica: 98% of children under 5, 26.9% of women aged 20-24Jordan: 98% of children under 5, 9.9% of women aged 20-24Kazakhstan: 99.7% of children under 5, 6.1% of women aged 20-24Kenya: 66.9% of children under 5, 12.5% of women aged 20-24Kyrgyz Republic: 98.9% of children under 5, 9.2% of women aged 20-24Cambodia: 73.3% of children under 5, 17.9% of women aged 20-24Kiribati: 91.6% of children under 5, 18.4% of women aged 20-24Lao PDR: 73% of children under 5, 30.5% of women aged 20-24Lebanon: 98.9% of children under 5, 6% of women aged 20-24Liberia: 66.3% of children under 5, 24.9% of women aged 20-24St. Lucia: 92% of children under 5, 24% of women aged 20-24Lesotho: 44.5% of children under 5, 13.4% of women aged 20-24Lithuania: 100% of children under 5, 0.2% of women aged 20-24Morocco: 96.9% of children under 5, 13.7% of women aged 20-24Moldova: 99.6% of children under 5, 12.2% of women aged 20-24Madagascar: 73.8% of children under 5, 38.8% of women aged 20-24Maldives: 98.8% of children under 5, 2.2% of women aged 20-24Mexico: 97% of children under 5, 18.2% of women aged 20-24North Macedonia: 99.8% of children under 5, 7.5% of women aged 20-24Mali: 86.7% of children under 5, 48.5% of women aged 20-24Myanmar: 81.3% of children under 5, 16% of women aged 20-24Montenegro: 99.4% of children under 5, 5.8% of women aged 20-24Mongolia: 99.6% of children under 5, 8.1% of women aged 20-24Mozambique: 55% of children under 5, 48.4% of women aged 20-24Mauritania: 44.8% of children under 5, 36.6% of women aged 20-24Malawi: 67.2% of children under 5, 38.7% of women aged 20-24Namibia: 78.1% of children under 5, 6.9% of women aged 20-24Niger: 63.9% of children under 5, 76.3% of women aged 20-24Nigeria: 42.6% of children under 5, 33.4% of women aged 20-24Nicaragua: 84.7% of children under 5, 35.2% of women aged 20-24Norway: 100% of children under 5, 0% of women aged 20-24Nepal: 77.2% of children under 5, 34.9% of women aged 20-24Naoero: 95.9% of children under 5, 18.2% of women aged 20-24Oman: 100% of children under 5, 4% of women aged 20-24Pakistan: 42.2% of children under 5, 18.3% of women aged 20-24Panama: 96.7% of children under 5, 26.4% of women aged 20-24Peru: 96.4% of children under 5, 17.9% of women aged 20-24Philippines: 91.8% of children under 5, 9.4% of women aged 20-24Papua New Guinea: 13.4% of children under 5, 27.3% of women aged 20-24Paraguay: 71% of children under 5, 21.6% of women aged 20-24West Bank and Gaza: 99.2% of children under 5, 13.4% of women aged 20-24Qatar: 100% of children under 5, 1.7% of women aged 20-24Romania: 100% of children under 5, 6.9% of women aged 20-24Russian Federation: 100% of children under 5, 6.2% of women aged 20-24Rwanda: 85.6% of children under 5, 5.5% of women aged 20-24Saudi Arabia: 99.2% of children under 5, 3.4% of women aged 20-24Sudan: 67.3% of children under 5, 34.2% of women aged 20-24Senegal: 78.7% of children under 5, 30.2% of women aged 20-24Singapore: 99.9% of children under 5, 0.1% of women aged 20-24Solomon Islands: 88% of children under 5, 21.3% of women aged 20-24Sierra Leone: 90.4% of children under 5, 29.6% of women aged 20-24El Salvador: 91.2% of children under 5, 19.7% of women aged 20-24Serbia: 99.9% of children under 5, 5.5% of women aged 20-24Sao Tome and Principe: 98.6% of children under 5, 28% of women aged 20-24Suriname: 98.3% of children under 5, 36% of women aged 20-24Eswatini: 53.5% of children under 5, 1.9% of women aged 20-24Turks and Caicos Islands: 99.2% of children under 5, 23.3% of women aged 20-24Chad: 25.7% of children under 5, 60.6% of women aged 20-24Togo: 82.9% of children under 5, 24.8% of women aged 20-24Thailand: 99.8% of children under 5, 17% of women aged 20-24Tajikistan: 95.8% of children under 5, 8.8% of women aged 20-24Turkmenistan: 99.9% of children under 5, 6.1% of women aged 20-24Timor-Leste: 60.4% of children under 5, 14.9% of women aged 20-24Tonga: 97.7% of children under 5, 10.1% of women aged 20-24Trinidad and Tobago: 96.5% of children under 5, 4.2% of women aged 20-24Tunisia: 99.9% of children under 5, 2.4% of women aged 20-24Turkiye: 98.4% of children under 5, 14.7% of women aged 20-24Tuvalu: 87.2% of children under 5, 1.8% of women aged 20-24Tanzania: 26.4% of children under 5, 29.1% of women aged 20-24Uganda: 32.2% of children under 5, 34% of women aged 20-24Ukraine: 99.8% of children under 5, 9.1% of women aged 20-24Uruguay: 99.8% of children under 5, 24.6% of women aged 20-24Viet Nam: 96.1% of children under 5, 14.6% of women aged 20-24Vanuatu: 43.4% of children under 5, 20.9% of women aged 20-24Samoa: 66.9% of children under 5, 7.4% of women aged 20-24South Africa: 88.6% of children under 5, 3.6% of women aged 20-24Zambia: 14% of children under 5, 23.9% of women aged 20-24Zimbabwe: 48.7% of children under 5, 33.7% of women aged 20-24ETHFINGBRMLINERNORPNGSURSWZTCDZMB

best-fit line line after adjusting

Four ways to measure the link

MethodrpCountries
Standard (Pearson), not adjusted-0.5232.5e-10128
By rank (Spearman), not adjusted-0.6394.7e-16128
Standard (Pearson), adjusted for national income-0.2320.009128
By rank (Spearman), adjusted for national income-0.3310.000128

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 128 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: +0.291 (a minus sign means it grew).

How solid is it?

Leaving out one country at a time, r ranges from -0.256 (without SWZ) to -0.198 (without TCD). 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 (+0.034).

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 & Pacific19-0.36
Europe & Central Asia22-0.16
Latin America & Caribbean25+0.02
Middle East, North Africa, Afghanistan & Pakistan15-0.26
Sub-Saharan Africa42-0.25

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 third43-0.29
Middle third42-0.24
Richest third43-0.25

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
Christians76-0.14
Muslims37-0.45

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
France23-0.60
Never a European colony16-0.67
Spain19-0.25
United Kingdom41-0.17

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 = -0.204 after dropping 8 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 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 children under 5
% of women aged 20-24		Years
Russian Federation RUS100%6.2%2022, 2017
Romania ROU100%6.9%2020, 2021
Qatar QAT100%1.7%2020, 2023
Oman OMN100%4%2018, 2014
Norway NOR100%0%2022
Lithuania LTU100%0.2%2020, 2022
Israel ISR100%0.8%2022
United Kingdom GBR100%0%2022, 2021
Finland FIN100%0.1%2022, 2017
Denmark DNK100%0.7%2019, 2021
Belarus BLR100%4.7%2019
Belgium BEL100%0.1%2022, 2020
Tunisia TUN99.9%2.4%2018, 2023
Turkmenistan TKM99.9%6.1%2019, 2024
Serbia SRB99.9%5.5%2019

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

Sources

Birth registration

Completeness of birth registration (%)

UNICEF · CC BY 4.0 · updated quarterly

A measure of how far the state reaches: whether it knows a child exists. Based on surveys and sparse. It is near 100 across the rich world, so all the variation is at the other end.

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.

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 Birth registration and Married by 18

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

More links with Birth registration or Married by 18