placestats

Basic water access vs. Secondary enrollment

Holds up after adjusting for income

Across 186 countries, Basic water access and Secondary enrollment rise and fall together at r = +0.73 (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 (q = 0.021, 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. Caution: direction is not consistent across regions.

Comparing countries across the middle half of basic water access, 88.2% to 99.8% of population, secondary enrollment is better by 17.2% gross at the top of that range than the bottom. Comparing only countries with similar national income, the gap is 8.86% gross.

Link before adjusting (r)+0.727p = 7.7e-32 · 186 countries
After adjusting for national income+0.352p = 8.7e-7 · likely range [+0.22, +0.47]
p, allowing for regions0.001standard error 0.059 · 7 regions
Check for luck (q)0.021across 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.

Basic water access · % of populationlink with income +0.85 · proxy
Secondary enrollment · % grosslink with income +0.71 · 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

Basic water access · % of population →Secondary enrollment · % gross →35.7%100%3.35%143%Aruba: 96.7% of population, 124% grossAfghanistan: 80.8% of population, 59.6% grossAngola: 68% of population, 51.5% grossAlbania: 95.1% of population, 108% grossAndorra: 100% of population, 102% grossUnited Arab Emirates: 100% of population, 102% grossArgentina: 99% of population, 106% grossArmenia: 99.9% of population, 90.9% grossAntigua and Barbuda: 98.9% of population, 109% grossAustralia: 100% of population, 132% grossAustria: 100% of population, 101% grossAzerbaijan: 97.7% of population, 91.1% grossBurundi: 65.9% of population, 23.1% grossBelgium: 100% of population, 143% grossBenin: 69.6% of population, 43.6% grossBurkina Faso: 50% of population, 30% grossBangladesh: 98.8% of population, 64.3% grossBulgaria: 99.2% of population, 94.8% grossBahrain: 99.9% of population, 98.8% grossBahamas, The: 98.9% of population, 79.5% grossBosnia and Herzegovina: 96.1% of population, 87.9% grossBelarus: 99.9% of population, 94.8% grossBelize: 94.8% of population, 86.5% grossBermuda: 100% of population, 74.4% grossBolivia: 93.4% of population, 90.5% grossBrazil: 100% of population, 104% grossBarbados: 99.2% of population, 104% grossBrunei Darussalam: 100% of population, 91.8% grossBhutan: 99.5% of population, 86.2% grossBotswana: 91.8% of population, 70.6% grossCentral African Republic: 36.5% of population, 15.8% grossCanada: 98.3% of population, 104% grossSwitzerland: 100% of population, 101% grossChile: 99.1% of population, 106% grossChina: 96.1% of population, 92.3% grossCote d'Ivoire: 77.2% of population, 65.3% grossCameroon: 71.4% of population, 44.8% grossCongo, Dem. Rep.: 35.7% of population, 55.5% grossCongo, Rep.: 73.5% of population, 50.5% grossColombia: 97.1% of population, 102% grossComoros: 85.1% of population, 54.8% grossCabo Verde: 92.3% of population, 96.4% grossCosta Rica: 99.8% of population, 122% grossCuracao: 100% of population, 89.9% grossCayman Islands: 95.5% of population, 84.8% grossCyprus: 99.7% of population, 107% grossCzechia: 98.7% of population, 97.6% grossGermany: 100% of population, 100% grossDominica: 97% of population, 103% grossDenmark: 100% of population, 126% grossDominican Republic: 97.5% of population, 76.4% grossAlgeria: 92.4% of population, 105% grossEcuador: 92.1% of population, 92.8% grossEgypt, Arab Rep.: 97.3% of population, 84.8% grossSpain: 99.9% of population, 119% grossEstonia: 100% of population, 109% grossEthiopia: 55.6% of population, 33.9% grossFinland: 100% of population, 142% grossFiji: 95.6% of population, 98.1% grossFrance: 100% of population, 104% grossGabon: 88.6% of population, 70.3% grossUnited Kingdom: 100% of population, 112% grossGeorgia: 97.3% of population, 101% grossGhana: 89.9% of population, 75.7% grossGuinea: 74.2% of population, 38.6% grossGambia, The: 87.1% of population, 107% grossGreece: 100% of population, 105% grossGrenada: 95.6% of population, 101% grossGuatemala: 93.2% of population, 49.6% grossGuyana: 95.6% of population, 91.4% grossHong Kong SAR, China: 100% of population, 107% grossHonduras: 95.7% of population, 51.8% grossCroatia: 99.9% of population, 105% grossHungary: 100% of population, 107% grossIndonesia: 89% of population, 97.2% grossIndia: 95.7% of population, 79.6% grossIreland: 97.1% of population, 131% grossIran, Islamic Rep.: 97.9% of population, 85.1% grossIceland: 100% of population, 109% grossIsrael: 100% of population, 98.5% grossItaly: 99.9% of population, 101% grossJamaica: 87.6% of population, 84.5% grossJordan: 99.3% of population, 91.8% grossJapan: 99.2% of population, 102% grossKazakhstan: 97.8% of population, 97.6% grossKenya: 65.6% of population, 84.3% grossKyrgyz Republic: 94.9% of population, 91.7% grossCambodia: 82.8% of population, 58.8% grossKiribati: 79.1% of population, 90.3% grossSt. Kitts and Nevis: 98.6% of population, 138% grossKorea, Rep.: 100% of population, 96.3% grossKuwait: 100% of population, 95.4% grossLao PDR: 95.9% of population, 50.5% grossLebanon: 92.6% of population, 63.8% grossLiberia: 78.8% of population, 37.7% grossSt. Lucia: 98.1% of population, 87.9% grossSri Lanka: 90.2% of population, 88% grossLesotho: 78.1% of population, 59.4% grossLithuania: 99.9% of population, 105% grossLuxembourg: 100% of population, 109% grossLatvia: 98.8% of population, 101% grossMacao SAR, China: 100% of population, 94.7% grossMorocco: 92.2% of population, 90% grossMoldova: 92.7% of population, 99.3% grossMadagascar: 55.3% of population, 34.1% grossMaldives: 99.8% of population, 79.4% grossMexico: 99.5% of population, 103% grossMarshall Islands: 87.4% of population, 85.8% grossNorth Macedonia: 98.2% of population, 90.1% grossMali: 86.4% of population, 38.9% grossMalta: 100% of population, 103% grossMyanmar: 85.7% of population, 77% grossMontenegro: 99.3% of population, 93.9% grossMongolia: 86.1% of population, 96.8% grossMozambique: 66.6% of population, 37.2% grossMauritania: 77.3% of population, 36% grossMauritius: 99.9% of population, 90.7% grossMalawi: 73.1% of population, 36.6% grossMalaysia: 97.9% of population, 80.3% grossNamibia: 86.5% of population, 82% grossNiger: 53.4% of population, 19.9% grossNigeria: 82.2% of population, 46.9% grossNetherlands: 100% of population, 138% grossNorway: 100% of population, 116% grossNepal: 93.6% of population, 90.4% grossNaoero: 97.8% of population, 94.5% grossNew Zealand: 100% of population, 114% grossOman: 92.7% of population, 95.1% grossPakistan: 90.7% of population, 48.3% grossPanama: 95.3% of population, 76.6% grossPeru: 95.6% of population, 108% grossPhilippines: 95.9% of population, 85.3% grossPalau: 99.5% of population, 95.7% grossPapua New Guinea: 53.3% of population, 52.1% grossPoland: 90.1% of population, 108% grossPuerto Rico (US): 100% of population, 81.5% grossPortugal: 99.3% of population, 120% grossParaguay: 99.6% of population, 79.1% grossWest Bank and Gaza: 98.8% of population, 89.1% grossQatar: 100% of population, 99.6% grossRomania: 100% of population, 81.6% grossRussian Federation: 96.9% of population, 92.5% grossRwanda: 61.4% of population, 48.8% grossSaudi Arabia: 99% of population, 111% grossSudan: 64.9% of population, 43.5% grossSenegal: 88% of population, 44.1% grossSingapore: 100% of population, 103% grossSolomon Islands: 71.6% of population, 49% grossSierra Leone: 68.1% of population, 86.9% grossEl Salvador: 91.6% of population, 62.1% grossSan Marino: 100% of population, 60.4% grossSomalia, Fed. Rep.: 75.3% of population, 3.35% grossSerbia: 95.4% of population, 89.8% grossSao Tome and Principe: 78% of population, 90.4% grossSuriname: 98% of population, 76.1% grossSlovak Republic: 99.8% of population, 93.2% grossSlovenia: 99.6% of population, 108% grossSweden: 99.8% of population, 132% grossEswatini: 80.4% of population, 82% grossSint Maarten (Dutch part): 99.3% of population, 111% grossSeychelles: 97.7% of population, 70.8% grossSyrian Arab Republic: 94.1% of population, 38.7% grossTurks and Caicos Islands: 98.8% of population, 120% grossChad: 52.2% of population, 23.5% grossTogo: 64.8% of population, 63.4% grossThailand: 100% of population, 92.1% grossTajikistan: 89.2% of population, 86.9% grossTurkmenistan: 99.9% of population, 94.6% grossTimor-Leste: 87.3% of population, 84.7% grossTonga: 98.9% of population, 92.4% grossTrinidad and Tobago: 99.3% of population, 95.7% grossTunisia: 96.7% of population, 90.3% grossTurkiye: 96% of population, 118% grossTuvalu: 98.7% of population, 90.7% grossTanzania: 64.6% of population, 28.2% grossUkraine: 93.5% of population, 86.2% grossUruguay: 99.6% of population, 119% grossUnited States: 100% of population, 97.5% grossUzbekistan: 97.3% of population, 98.1% grossSt. Vincent and the Grenadines: 97.7% of population, 125% grossViet Nam: 98.8% of population, 93.4% grossVanuatu: 87.1% of population, 135% grossSamoa: 99.4% of population, 87.4% grossSouth Africa: 90.2% of population, 104% grossZambia: 73.4% of population, 56.8% grossZimbabwe: 67.2% of population, 52.4% grossBELCAFCODFINKENLAONERNLDSOMSYRVUT

best-fit line line after adjusting

Four ways to measure the link

MethodrpCountries
Standard (Pearson), not adjusted+0.7277.7e-32186
By rank (Spearman), not adjusted+0.6591.5e-24186
Standard (Pearson), adjusted for national income+0.3528.7e-7186
By rank (Spearman), adjusted for national income+0.1620.028186

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 186 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 +0.338 (without TCD) to +0.384 (without COD). 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: COD (+0.032).

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 & Pacific30+0.37
Europe & Central Asia50-0.09
Latin America & Caribbean35+0.32
Middle East, North Africa, Afghanistan & Pakistan19+0.15
Sub-Saharan Africa43+0.21

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+0.35
Middle third62+0.11
Richest third62+0.09

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+0.32
Muslims45+0.40

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+0.03
Never a European colony21+0.64
Spain17+0.29
United Kingdom60+0.34

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 = +0.277 after dropping 20 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 25years. 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 also shows up within countries over time (r = +0.279). It holds even when looking only at changes from one year to the next (r = +0.093). This is the strongest kind of evidence available here: it holds when each country is compared only with itself, and it is not just a product of shared trends.

Across countries (adjusted)+0.352for comparison
Within countries+0.513each country vs itself
…and vs the same year elsewhere+0.279q = 0.000 · 186 countries
Year-on-year changes+0.093q = 0.000
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.

3,479 country-years (one country in one year), 186 countries, 2000–2024, about 19 years each on average. Share of the variation that happens within countries over time: 5% for Basic water access, 10% for Secondary enrollment. 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 Secondary enrollment trails Basic water access →lag -10: r = 0.164 (n = 2,859)lag -9: r = 0.185 (n = 2,927)lag -8: r = 0.216 (n = 2,990)lag -7: r = 0.243 (n = 3,052)lag -6: r = 0.266 (n = 3,114)lag -5: r = 0.286 (n = 3,169)lag -4: r = 0.293 (n = 3,245)lag -3: r = 0.296 (n = 3,325)lag -2: r = 0.295 (n = 3,405)lag -1: r = 0.287 (n = 3,486)lag +0: r = 0.279 (n = 3,479)lag +1: r = 0.266 (n = 3,372)lag +2: r = 0.244 (n = 3,233)lag +3: r = 0.228 (n = 3,099)lag +4: r = 0.211 (n = 2,967)lag +5: r = 0.206 (n = 2,824)lag +6: r = 0.200 (n = 2,680)lag +7: r = 0.189 (n = 2,533)lag +8: r = 0.174 (n = 2,386)lag +9: r = 0.156 (n = 2,237)lag +10: r = 0.141 (n = 2,086)

Same year (lag 0): +0.279. 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


% of population
% gross		Years
Thailand THA100%92.1%2024, 2025
Singapore SGP100%103%2024, 2023
Puerto Rico (US) PRI100%81.5%2024
New Zealand NZL100%114%2024
Norway NOR100%116%2024
Netherlands NLD100%138%2024, 2023
Malta MLT100%103%2024, 2023
Macao SAR, China MAC100%94.7%2024
Luxembourg LUX100%109%2024
Kuwait KWT100%95.4%2024, 2015
Korea, Rep. KOR100%96.3%2024
Iceland ISL100%109%2024, 2023
Hungary HUN100%107%2024
Hong Kong SAR, China HKG100%107%2024
Greece GRC100%105%2024, 2023

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

Sources

Basic water access

People using at least basic drinking water services (% of population)

World Bank · CC BY 4.0 · updated quarterly

Secondary enrollment

School enrollment, secondary (% gross)

UNESCO Institute for Statistics · CC BY 4.0 · updated quarterly

How this was computed

Data used: most recent value in 2010-2025; values come from 2012–2025. 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 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 Basic water access and Secondary enrollment

This page shows that two measures go together. It does not show that Basic water access changes Secondary enrollment, or the reverse. These figures also describe countries, not individual people. See the ecological fallacy.

More links with Basic water access or Secondary enrollment