Do Ethnic diversity and Tertiary enrollment go together across countries?

Across 139 countries the link before adjusting for anything is r = -0.48, on a scale from -1 (opposite) to +1 (in step). A version that uses only each country's rank gives -0.50.

Does the link hold within countries over time, not just across countries?

Comparing each country only with itself across 1990-2013, and setting aside what happened worldwide in each year, the link is +0.109 (130 countries, 1,980 country-years). Using year-to-year changes, it is +0.045.

Does Ethnic diversity cause Tertiary enrollment?

This analysis cannot answer that. It shows only that the two go together. A link between two country measures, adjusted or not, does not show that either one changes the other. Country figures also say nothing about individual people.

Ethnic diversity vs. Tertiary enrollment

Holds up after adjusting for income

Across 139 countries, Ethnic diversity and Tertiary enrollment rise and fall together at r = -0.48 (on a scale from −1 to +1, where 0 means no link). Comparing only countries with similar income (GDP per person) shrinks it to -0.28 (q = 0.0099, allowing for the many pairs tested). Much of the first figure is that both measures rise with national income, but a weak negative link remains.

Comparing countries across the middle half of ethnic diversity, 0.244 to 0.698 points, tertiary enrollment is worse by 28.9% gross at the top of that range than the bottom. Comparing only countries with similar national income, the gap is 11.2% gross.

Link before adjusting (r)-0.482p = 1.8e-9 · 139 countries

After adjusting for national income-0.275p = 0.001 · likely range [-0.42, -0.11]

p, allowing for regions0.000standard error 0.037 · 7 regions

Check for luck (q)0.010across 13,797 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.

Ethnic diversity · index, 0 to 1link with income -0.37 · moderate

Tertiary enrollment · % grosslink with income +0.75 · high

“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	-0.482	1.8e-9	139
By rank (Spearman), not adjusted	-0.501	3.4e-10	139
Standard (Pearson), adjusted for national income	-0.275	0.001	139
By rank (Spearman), adjusted for national income	-0.306	0.000	139

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 139 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: +0.207 (a minus sign means it grew).

How solid is it?

Leaving out one country at a time, r ranges from -0.289 (without BGD) to -0.250 (without GUY). 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: GUY (+0.026).

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	16	-0.17
Europe & Central Asia	43	-0.01
Latin America & Caribbean	19	-0.24
Middle East, North Africa, Afghanistan & Pakistan	18	-0.40
Sub-Saharan Africa	37	-0.17

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	47	-0.33
Middle third	46	-0.10
Richest third	46	-0.43

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	80	-0.23
Muslims	41	-0.33

By last european coloniser

	n	r
France	21	-0.60
Never a European colony	21	-0.04
Spain	17	-0.03
United Kingdom	39	-0.23

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 = -0.266 after dropping 1 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 24years. So a link here can’t come from anything about a country that stays the same, such as its history, geography, institutions or culture.

Within countries over time, there is no link that is clearly more than chance (r = +0.109, comparing each country only with itself over the years, and each year only with the same year elsewhere). Whatever the cross-country picture shows, countries whose ethnic diversity moved did not tend to see their tertiary enrollment move with it.

Across countries (adjusted)-0.275for comparison

Within countries+0.148each country vs itself

…and vs the same year elsewhere+0.109q = 0.403 · 130 countries

Year-on-year changes+0.045q = 0.539

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.

1,980 country-years (one country in one year), 130 countries, 1990–2013, about 15 years each on average. Share of the variation that happens within countries over time: 1% for Ethnic diversity, 12% for Tertiary 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

Same year (lag 0): +0.109. 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

	index, 0 to 1	% gross	Years
Liberia LBR	0.889	10.8%	2013, 2012
Uganda UGA	0.883	4.62%	2013, 2014
Togo TGO	0.88	14.9%	2013, 2020
Nepal NPL	0.86	21.3%	2013, 2024
South Africa ZAF	0.856	23.5%	2013, 2023
Chad TCD	0.855	4.4%	2013, 2020
Kenya KEN	0.855	10.4%	2013, 2024
Mali MLI	0.852	5.13%	2013, 2015
Nigeria NGA	0.85	9.74%	2013, 2011
Philippines PHL	0.807	47.4%	2013, 2024
Indonesia IDN	0.803	44.9%	2013, 2023
Timor-Leste TLS	0.802	31%	2013, 2023
Malawi MWI	0.791	2.71%	2013, 2022
Central African Republic CAF	0.79	2.78%	2013, 2012
Ethiopia ETH	0.783	5.92%	2013, 2014

Drazanova, L. (2019), Historical Index of Ethnic Fractionalization Dataset (HIEF), Harvard Dataverse, doi:10.7910/DVN/4JQRCL
World Bank, World Development Indicators

Sources

Ethnic diversity

Ethnic fractionalization index

Lenka Drazanova · CC0 1.0 · updated one edition (2019), annual values 1945-2013

The chance that two people picked at random in a country belong to different ethnic groups, from 0 (everyone in one group) to close to 1 (many small groups). It measures how mixed a country is, not which groups live there. The groups are those each country's own sources use, so where the lines are drawn differs from country to country. Yearly from 1945 to 2013, so the latest value is from 2013. No "better" direction is set.

Tertiary enrollment

School enrollment, tertiary (% 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 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 7 World Bank regions. The q-value corrects for testing all 13,797 pairs at once, using the Benjamini–Hochberg method. Underlying data last updated DYB 2024. How the country data works · explore Ethnic diversity and Tertiary enrollment

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