placestats

Age at childbearing vs. Migrant share of population

Holds up after adjusting for income

Across 198 countries, Age at childbearing and Migrant share of population rise and fall together at r = +0.42 (on a scale from −1 to +1, where 0 means no link). Comparing only countries with similar income (GDP per person) shrinks it to +0.22 (q = 0.037, allowing for the many pairs tested). Much of the first figure is that both measures rise with national income, but a weak positive link remains.

Comparing countries across the middle half of age at childbearing, 28.2 to 30.4 years, migrant share of population is 9.19% of population higher at the top of that range than the bottom. Comparing only countries with similar national income, the gap is 4.49% of population.

Link before adjusting (r)+0.417p = 1.0e-9 · 198 countries
After adjusting for national income+0.223p = 0.002 · likely range [+0.09, +0.35]
p, allowing for regions0.003standard error 0.046 · 7 regions
Check for luck (q)0.037across 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.

Age at childbearing · yearslink with income +0.44 · moderate
Migrant share of population · % of populationlink with income +0.73 · high

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

Every country as a dot

Age at childbearing · years →Migrant share of population · % of population →25.333.40.1%76.7%Aruba: 28.8 years, 68% of populationAfghanistan: 30.4 years, 0.2% of populationAngola: 28.6 years, 1.8% of populationAlbania: 29.1 years, 1.7% of populationAndorra: 32.5 years, 59.1% of populationUnited Arab Emirates: 31.9 years, 74% of populationArgentina: 29.1 years, 4.3% of populationArmenia: 27.8 years, 9.2% of populationAntigua and Barbuda: 28.3 years, 32.5% of populationAustralia: 31.4 years, 30.4% of populationAustria: 31.2 years, 25.5% of populationAzerbaijan: 25.9 years, 2.1% of populationBurundi: 30.2 years, 2.8% of populationBelgium: 31 years, 20% of populationBenin: 29.1 years, 2.9% of populationBurkina Faso: 29.2 years, 3.1% of populationBangladesh: 26 years, 1.7% of populationBulgaria: 27.9 years, 4.4% of populationBahrain: 30 years, 52.3% of populationBahamas, The: 28.8 years, 16.8% of populationBosnia and Herzegovina: 29 years, 1.1% of populationBelarus: 28.7 years, 11.6% of populationBelize: 27.2 years, 16.5% of populationBermuda: 32.1 years, 31.2% of populationBolivia: 28.1 years, 1.5% of populationBrazil: 27.8 years, 0.7% of populationBarbados: 27.7 years, 12.5% of populationBrunei Darussalam: 30.7 years, 25.9% of populationBhutan: 29.9 years, 7% of populationBotswana: 28.7 years, 4.6% of populationCentral African Republic: 29 years, 1.8% of populationCanada: 31.4 years, 22.2% of populationSwitzerland: 32.3 years, 31.1% of populationChile: 31.2 years, 7.8% of populationChina: 29 years, 0.1% of populationCote d'Ivoire: 29 years, 9% of populationCameroon: 28.4 years, 2.2% of populationCongo, Dem. Rep.: 30.1 years, 1% of populationCongo, Rep.: 28.6 years, 6.1% of populationColombia: 26.6 years, 5.8% of populationComoros: 30.2 years, 1.4% of populationCabo Verde: 28.6 years, 3.1% of populationCosta Rica: 28.2 years, 12.2% of populationCuracao: 30 years, 43.1% of populationCayman Islands: 30.6 years, 42.9% of populationCyprus: 31.7 years, 14.9% of populationCzechia: 30.4 years, 9.5% of populationGermany: 31.5 years, 19.8% of populationDjibouti: 31.5 years, 10.8% of populationDominica: 28.2 years, 12.7% of populationDenmark: 31.6 years, 14.2% of populationDominican Republic: 27.4 years, 6.5% of populationAlgeria: 31.5 years, 0.6% of populationEcuador: 27.4 years, 4.1% of populationEgypt, Arab Rep.: 28 years, 1% of populationSpain: 32.5 years, 18.5% of populationEstonia: 31 years, 14.9% of populationEthiopia: 29.1 years, 0.9% of populationFinland: 31.5 years, 9.2% of populationFiji: 28.8 years, 1.5% of populationFrance: 31.6 years, 13.8% of populationFaroe Islands: 30.3 years, 14.6% of populationMicronesia, Fed. Sts.: 28.9 years, 2.6% of populationGabon: 28.5 years, 17.7% of populationUnited Kingdom: 30.9 years, 17.1% of populationGeorgia: 28.5 years, 2.1% of populationGhana: 29.5 years, 1.5% of populationGuinea: 28.3 years, 0.8% of populationGambia, The: 29.8 years, 8.6% of populationGuinea-Bissau: 29.5 years, 0.7% of populationEquatorial Guinea: 27 years, 13.2% of populationGreece: 32 years, 14.2% of populationGrenada: 28.6 years, 6.3% of populationGreenland: 27.9 years, 10.4% of populationGuatemala: 27.3 years, 0.5% of populationGuyana: 27 years, 6.5% of populationHong Kong SAR, China: 32.9 years, 41.3% of populationHonduras: 27.2 years, 0.4% of populationCroatia: 30.7 years, 13.6% of populationHaiti: 29.6 years, 0.2% of populationHungary: 30 years, 7.1% of populationIndonesia: 28.9 years, 0.2% of populationIndia: 27.5 years, 0.3% of populationIreland: 32.7 years, 23.1% of populationIran, Islamic Rep.: 28.8 years, 4.2% of populationIraq: 28.6 years, 0.8% of populationIceland: 30.8 years, 25.1% of populationIsrael: 30.9 years, 22.3% of populationItaly: 32.3 years, 11% of populationJamaica: 27.9 years, 0.8% of populationJordan: 29.8 years, 45.7% of populationJapan: 31.9 years, 2.8% of populationKazakhstan: 29 years, 10.1% of populationKenya: 28.2 years, 1.8% of populationKyrgyz Republic: 28.5 years, 2.7% of populationCambodia: 27.9 years, 0.5% of populationKiribati: 29.1 years, 2.5% of populationSt. Kitts and Nevis: 27.6 years, 17% of populationKorea, Rep.: 33.4 years, 3.5% of populationKuwait: 30.3 years, 67.3% of populationLao PDR: 26.3 years, 0.7% of populationLebanon: 29.2 years, 24.5% of populationLiberia: 28.3 years, 1.3% of populationLibya: 31.9 years, 12.2% of populationSt. Lucia: 28.8 years, 4.5% of populationSri Lanka: 29.6 years, 0.2% of populationLesotho: 27.9 years, 0.6% of populationLithuania: 30.3 years, 6.1% of populationLuxembourg: 32.3 years, 51.2% of populationLatvia: 30.3 years, 11.8% of populationMacao SAR, China: 32.1 years, 59.3% of populationMorocco: 29.9 years, 0.3% of populationMoldova: 28 years, 6.2% of populationMadagascar: 27.9 years, 0.1% of populationMaldives: 30.2 years, 14.2% of populationMexico: 26.8 years, 1.3% of populationMarshall Islands: 27.1 years, 8.8% of populationNorth Macedonia: 29 years, 8.3% of populationMali: 28.9 years, 2.2% of populationMalta: 30.9 years, 37% of populationMyanmar: 28.8 years, 0.1% of populationMontenegro: 30.2 years, 14.4% of populationMongolia: 29.3 years, 0.6% of populationMozambique: 28.4 years, 1% of populationMauritania: 30.2 years, 3.8% of populationMauritius: 29.1 years, 2.3% of populationMalawi: 27.7 years, 0.9% of populationMalaysia: 31 years, 10.7% of populationNamibia: 28.9 years, 3.8% of populationNiger: 29.1 years, 1.7% of populationNigeria: 29.2 years, 0.6% of populationNicaragua: 26 years, 0.6% of populationNetherlands: 31.8 years, 16.2% of populationNorway: 31.6 years, 18.2% of populationNepal: 25.3 years, 1.6% of populationNaoero: 27.1 years, 21.3% of populationNew Zealand: 30.6 years, 28.2% of populationOman: 31.7 years, 43.2% of populationPakistan: 28.9 years, 1.7% of populationPanama: 27.3 years, 10.6% of populationPeru: 28.8 years, 5.4% of populationPhilippines: 29 years, 0.1% of populationPalau: 28.5 years, 29.5% of populationPapua New Guinea: 29.3 years, 0.3% of populationPoland: 29.9 years, 4.5% of populationPuerto Rico (US): 27.8 years, 6.9% of populationPortugal: 31.7 years, 10.8% of populationParaguay: 27.7 years, 2.6% of populationWest Bank and Gaza: 28.6 years, 5% of populationQatar: 30.4 years, 76.7% of populationRomania: 28.1 years, 3.4% of populationRussian Federation: 28.9 years, 5.3% of populationRwanda: 30.6 years, 3.6% of populationSaudi Arabia: 30.1 years, 40.3% of populationSudan: 29.8 years, 4.8% of populationSenegal: 29.9 years, 1.5% of populationSingapore: 32.3 years, 48.7% of populationSolomon Islands: 29.2 years, 0.3% of populationSierra Leone: 28.6 years, 0.6% of populationEl Salvador: 27.1 years, 0.7% of populationSan Marino: 32.8 years, 17.4% of populationSomalia, Fed. Rep.: 29.4 years, 0.4% of populationSerbia: 29.5 years, 10.6% of populationSao Tome and Principe: 28.5 years, 0.8% of populationSuriname: 28.4 years, 8.2% of populationSlovak Republic: 28.9 years, 5.9% of populationSlovenia: 30.4 years, 14.9% of populationSweden: 31.6 years, 21.4% of populationEswatini: 27.9 years, 2.7% of populationSint Maarten (Dutch part): 28.9 years, 69.5% of populationSeychelles: 27.6 years, 10.2% of populationSyrian Arab Republic: 28.8 years, 3.6% of populationTurks and Caicos Islands: 30.4 years, 61.1% of populationChad: 29.2 years, 6.3% of populationTogo: 29.1 years, 3% of populationThailand: 28.3 years, 4.4% of populationTajikistan: 26.5 years, 2.6% of populationTurkmenistan: 27.8 years, 2.6% of populationTimor-Leste: 29.4 years, 0.6% of populationTonga: 29.9 years, 3.4% of populationTrinidad and Tobago: 27.8 years, 7.5% of populationTunisia: 31.3 years, 0.5% of populationTurkiye: 29.2 years, 8.1% of populationTuvalu: 29.2 years, 2.6% of populationTanzania: 28.9 years, 0.7% of populationUganda: 28.3 years, 4.1% of populationUkraine: 28.1 years, 13.4% of populationUruguay: 29.2 years, 4.7% of populationUnited States: 29.9 years, 15.2% of populationUzbekistan: 27 years, 3.2% of populationSt. Vincent and the Grenadines: 28.2 years, 4.8% of populationVirgin Islands (U.S.): 27.7 years, 66.9% of populationViet Nam: 27.2 years, 0.3% of populationVanuatu: 28.1 years, 1% of populationSamoa: 29.3 years, 1.8% of populationSouth Africa: 28.3 years, 4.1% of populationZambia: 28.4 years, 1.2% of populationZimbabwe: 28.1 years, 2.6% of populationABWANDAREAZEDZAJPNKORMACNICNPLSXMVIR

best-fit line line after adjusting

Four ways to measure the link

MethodrpCountries
Standard (Pearson), not adjusted+0.4171.0e-9198
By rank (Spearman), not adjusted+0.4322.2e-10198
Standard (Pearson), adjusted for national income+0.2230.002198
By rank (Spearman), adjusted for national income+0.1790.012198

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 198 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: +0.194 (a minus sign means it grew).

How solid is it?

Leaving out one country at a time, r ranges from +0.205 (without AND) to +0.260 (without VIR). 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: VIR (+0.038).

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 & Pacific31+0.08
Europe & Central Asia52+0.36
Latin America & Caribbean38+0.32
Middle East, North Africa, Afghanistan & Pakistan22+0.12
Sub-Saharan Africa46-0.03

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 third66+0.29
Middle third66+0.13
Richest third66-0.03

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
Christians112+0.20
Muslims49+0.37

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+0.07
Never a European colony21+0.20
Spain20-0.05
United Kingdom63+0.36

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 = +0.298 after dropping 19 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 31years. 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 = +0.164) 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)+0.223for comparison
Within countries+0.229each country vs itself
…and vs the same year elsewhere+0.164q = 0.017 · 215 countries
Year-on-year changes—q = —
Read with care.
  • Almost all of the second indicator's variation is between countries, so the within-country estimate rests on a small part of the data.

1,505 country-years (one country in one year), 215 countries, 1990–2020, about 7 years each on average. Share of the variation that happens within countries over time: 24% for Age at childbearing, 3% for Migrant share of 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

0.20−0.2-100+10years Migrant share of population trails Age at childbearing →lag -10: r = 0.130 (n = 1,075)lag -9: r = 0.135 (n = 1,075)lag -8: r = 0.136 (n = 1,290)lag -7: r = 0.129 (n = 1,290)lag -6: r = 0.131 (n = 1,290)lag -5: r = 0.126 (n = 1,290)lag -4: r = 0.122 (n = 1,290)lag -3: r = 0.153 (n = 1,505)lag -2: r = 0.155 (n = 1,505)lag -1: r = 0.162 (n = 1,505)lag +0: r = 0.164 (n = 1,505)lag +1: r = 0.164 (n = 1,505)lag +2: r = 0.166 (n = 1,505)lag +3: r = 0.172 (n = 1,505)lag +4: r = 0.178 (n = 1,505)lag +5: r = 0.187 (n = 1,505)lag +6: r = 0.147 (n = 1,290)lag +7: r = 0.154 (n = 1,290)lag +8: r = 0.163 (n = 1,290)lag +9: r = 0.170 (n = 1,290)lag +10: r = 0.178 (n = 1,290)

Same year (lag 0): +0.164. 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.

The data


years
% of population		Years
Korea, Rep. KOR33.43.5%2023, 2024
Hong Kong SAR, China HKG32.941.3%2023, 2024
San Marino SMR32.817.4%2023, 2024
Ireland IRL32.723.1%2023, 2024
Spain ESP32.518.5%2023, 2024
Andorra AND32.559.1%2023, 2024
Luxembourg LUX32.351.2%2023, 2024
Italy ITA32.311%2023, 2024
Switzerland CHE32.331.1%2023, 2024
Singapore SGP32.348.7%2023, 2024
Macao SAR, China MAC32.159.3%2023, 2024
Bermuda BMU32.131.2%2023, 2024
Greece GRC3214.2%2023, 2024
Japan JPN31.92.8%2023, 2024
United Arab Emirates ARE31.974%2023, 2024

United Nations, Department of Economic and Social Affairs, Population Division: World Population Prospects 2024 and Estimates and Projections of Women of Reproductive Age Who Are Married or in a Union
World Bank, World Development Indicators

Sources

Age at childbearing

Mean age of mothers at childbearing

United Nations Department of Economic and Social Affairs, Population Division · via Our World in Data · CC BY 3.0 IGO · updated biennial

The average age of women giving birth in the year, based on how many births women of each age have. Later childbearing goes with fewer births, but not one for one. A country can have late but plentiful births, or early but few. No "better" direction is set.

Migrant share of population

International migrant stock (% of population)

UN Population Division, International Migrant Stock · CC BY 4.0 · updated quarterly

People living outside the country they were born in, as a share of the population. It counts people at one moment, while the net migration already on the site counts moves over a year. Published every five years until 2020, and for 2024.

How this was computed

Data used: most recent value in 2010-2025; values come from 2023–2024. 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 Age at childbearing and Migrant share of population

This page shows that two measures go together. It does not show that Age at childbearing changes Migrant share of population, or the reverse. These figures also describe countries, not individual people. See the ecological fallacy.

More links with Age at childbearing or Migrant share of population