Pupil-teacher ratio vs. Unintended pregnancy rate
Fades after adjusting for income
Across 134 countries, Pupil-teacher ratio and Unintended pregnancy rate rise and fall together at r = +0.60 (on a scale from −1 to +1, where 0 means no link). Comparing only countries with similar income (GDP per person) shrinks it to +0.13, which could easily be chance (q = 0.12, 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 unintended pregnancy rate, 34.6 to 86.7 per 1,000 women aged 15-49, pupil-teacher ratio is worse by 13.6 pupils per teacher at the top of that range than the bottom. Comparing only countries with similar national income, the gap is 2.31 pupils per teacher.
Link before adjusting (r)+0.596p = 3.1e-14 · 134 countries
After adjusting for national income+0.127p = 0.146 · likely range [-0.04, +0.29]
p, allowing for regions0.121standard error 0.070 · 7 regions
Check for luck (q)0.123across 14,952 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.
Pupil-teacher ratio · pupils per teacherlink with income -0.83 · proxy
Unintended pregnancy rate · per 1,000 women aged 15-49link with income -0.69 · 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
best-fit line line after adjusting
Four ways to measure the link
| Method | r | p | Countries |
|---|---|---|---|
| Standard (Pearson), not adjusted | +0.596 | 3.1e-14 | 134 |
| By rank (Spearman), not adjusted | +0.665 | 1.8e-18 | 134 |
| Standard (Pearson), adjusted for national income | +0.127 | 0.146 | 134 |
| By rank (Spearman), adjusted for national income | +0.208 | 0.016 | 134 |
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 134 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: +0.469 (a minus sign means it grew).
How solid is it?
Leaving out one country at a time, r ranges from +0.087 (without AGO) to +0.166 (without CAF). 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: AGO (-0.040).
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.
| n | r | ||
|---|---|---|---|
| East Asia & Pacific | 20 | +0.02 | |
| Europe & Central Asia | 41 | -0.06 | |
| Latin America & Caribbean | 23 | +0.01 | |
| Sub-Saharan Africa | 41 | -0.04 |
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.
| n | r | ||
|---|---|---|---|
| Poorest third | 45 | +0.13 | |
| Middle third | 44 | +0.18 | |
| Richest third | 45 | +0.34 |
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.
| n | r | ||
|---|---|---|---|
| Christians | 90 | +0.10 | |
| Muslims | 25 | +0.27 |
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.
| n | r | ||
|---|---|---|---|
| France | 20 | +0.26 | |
| Never a European colony | 15 | -0.24 | |
| Spain | 16 | -0.16 | |
| United Kingdom | 34 | +0.15 |
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 = +0.153 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
pupils per teacher | per 1,000 women aged 15-49 | Years | |
|---|---|---|---|
| Central African Republic CAF | 83.4 | 90.2 | 2016, 2019 |
| Rwanda RWA | 59.5 | 97.6 | 2018, 2019 |
| Malawi MWI | 58.7 | 115 | 2018, 2019 |
| Chad TCD | 56.9 | 59.6 | 2016, 2019 |
| Mozambique MOZ | 55.3 | 88.2 | 2018, 2019 |
| Ethiopia ETH | 55.1 | 79.5 | 2011, 2019 |
| Guinea-Bissau GNB | 51.9 | 99.5 | 2010, 2019 |
| Tanzania TZA | 50.6 | 105 | 2018, 2019 |
| Angola AGO | 50 | 120 | 2015, 2019 |
| Guinea GIN | 47.1 | 69.8 | 2016, 2019 |
| Cameroon CMR | 44.8 | 83.4 | 2018, 2019 |
| Congo, Rep. COG | 44.4 | 106 | 2012, 2019 |
| Pakistan PAK | 44.1 | 70.9 | 2018, 2019 |
| Uganda UGA | 42.7 | 145 | 2017, 2019 |
| Burundi BDI | 42.5 | 98.1 | 2018, 2019 |
World Bank, World Development Indicators
Bearak, J. M., Popinchalk, A., Beavin, C. et al. (2022), 'Country-specific estimates of unintended pregnancy and abortion incidence: a global comparative analysis of levels in 2015-2019', BMJ Global Health 7(3), e007151. Guttmacher Institute. Supplementary appendix, tables A3-A5.
Sources
Pupil-teacher ratio
Pupil-teacher ratio, primary
UNESCO Institute for Statistics · CC BY 4.0 · updated quarterly
The World Bank's copy stops at 2019.
Unintended pregnancy rate
Unintended pregnancies per 1,000 women aged 15-49 (model estimate, 2015-2019)
Guttmacher Institute (Bearak et al. 2022, BMJ Global Health) · CC BY-NC 4.0 · updated one edition (2015-2019 estimates, published 2022)
The Guttmacher Institute's estimate of pregnancies that were not wanted then or not wanted at all, per 1,000 women aged 15 to 49, averaged over 2015-2019. Whether a pregnancy was intended comes from what women say in surveys, so it is an estimate built from those surveys and a statistical model. Each figure has a range: Uganda's is 145, but it could be from 123 to 169.
How this was computed
Data used: most recent value in 2010-2025; values come from 2010–2019. 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 14,952 pairs at once, using the Benjamini–Hochberg method. Underlying data last updated DYB 2024. How the country data works · explore Pupil-teacher ratio and Unintended pregnancy rate
This page shows that two measures go together. It does not show that Pupil-teacher ratio changes Unintended pregnancy rate, or the reverse. These figures also describe countries, not individual people. See the ecological fallacy.
More links with Pupil-teacher ratio or Unintended pregnancy rate
- Redistribution vs Unintended pregnancy rate before -0.73 → after adjusting -0.47
- Gender Inequality Index vs Unintended pregnancy rate before +0.75 → after adjusting +0.46
- Adult literacy vs Pupil-teacher ratio before -0.73 → after adjusting -0.41
- Pupil-teacher ratio vs Secondary enrollment before -0.75 → after adjusting -0.40
- Informal employment vs Unintended pregnancy rate before +0.74 → after adjusting +0.39
- Maternal mortality vs Pupil-teacher ratio before +0.71 → after adjusting +0.37
- European ancestry vs Unintended pregnancy rate before -0.65 → after adjusting -0.35
- Population growth vs Pupil-teacher ratio before +0.56 → after adjusting +0.35