Regime type vs. Tax revenue
Fades after adjusting for income
Across 136 countries, Regime type and Tax revenue rise and fall together at r = +0.53 (on a scale from −1 to +1, where 0 means no link). Comparing only countries with similar income (GDP per person) leaves r = +0.45, which could easily be chance (q = 0.051, allowing for the many pairs tested, and allowing for countries in the same region being alike).
Comparing countries across the middle half of regime type, 1 to 2 points, tax revenue is 3.79% of GDP higher at the top of that range than the bottom. Comparing only countries with similar national income, the gap is 3.64% of GDP.
Link before adjusting (r)+0.530p = 3.2e-11 · 136 countries
After adjusting for national income+0.449p = 4.9e-8 · likely range [+0.30, +0.57]
p, allowing for regions0.005standard error 0.105 · 7 regions
Check for luck (q)0.051across 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.
Regime type · regime category (0-3)link with income +0.49 · moderate
Tax revenue · % of GDPlink with income +0.33 · moderate
“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 | +0.530 | 3.2e-11 | 136 |
| By rank (Spearman), not adjusted | +0.527 | 4.5e-11 | 136 |
| Standard (Pearson), adjusted for national income | +0.449 | 4.9e-8 | 136 |
| By rank (Spearman), adjusted for national income | +0.427 | 2.4e-7 | 136 |
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 136 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: +0.081 (a minus sign means it grew).
How solid is it?
Leaving out one country at a time, r ranges from +0.412 (without ARE) to +0.475 (without SWZ). 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: ARE (-0.036).
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 | 17 | +0.77 | |
| Europe & Central Asia | 46 | +0.20 | |
| Latin America & Caribbean | 19 | +0.28 | |
| Middle East, North Africa, Afghanistan & Pakistan | 12 | +0.59 | |
| Sub-Saharan Africa | 34 | +0.44 |
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 | 46 | +0.43 | |
| Middle third | 45 | +0.22 | |
| Richest third | 45 | +0.61 |
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 | +0.26 | |
| Muslims | 28 | +0.46 |
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 | 14 | +0.12 | |
| Never a European colony | 16 | +0.37 | |
| Spain | 18 | +0.02 | |
| United Kingdom | 40 | +0.64 |
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 = +0.449 after dropping 0 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 35years. 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 = +0.022, 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 regime type moved did not tend to see their tax revenue move with it.
Across countries (adjusted)+0.449for comparison
Within countries+0.019each country vs itself
…and vs the same year elsewhere+0.022q = 0.187 · 141 countries
Year-on-year changes+0.024q = 0.179
3,586 country-years (one country in one year), 141 countries, 1990–2024, about 25 years each on average. Share of the variation that happens within countries over time: 15% for Regime type, 70% for Tax revenue. 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): +0.022. 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.
This curve peaks at the edge of the window (lag -10), so it is still drifting where the search stops. That pattern usually reflects a slow trend left over in the data, not a link with real timing. The peak value should not be read as the “true” link at the right lag.
The data
regime category (0-3) | % of GDP | Years | |
|---|---|---|---|
| Uruguay URY | 3 | 17.9% | 2025, 2024 |
| Trinidad and Tobago TTO | 3 | 16.8% | 2025, 2019 |
| Sweden SWE | 3 | 27.2% | 2025, 2024 |
| New Zealand NZL | 3 | 29.5% | 2025, 2024 |
| Norway NOR | 3 | 24.5% | 2025, 2024 |
| Netherlands NLD | 3 | 25.3% | 2025, 2024 |
| Latvia LVA | 3 | 17.6% | 2025, 2024 |
| Luxembourg LUX | 3 | 28.6% | 2025, 2024 |
| Lithuania LTU | 3 | 21.9% | 2025, 2024 |
| Korea, Rep. KOR | 3 | 13.3% | 2025, 2024 |
| Italy ITA | 3 | 25.6% | 2025, 2024 |
| Iceland ISL | 3 | 23.2% | 2025, 2023 |
| Ireland IRL | 3 | 17.9% | 2025, 2024 |
| France FRA | 3 | 22.8% | 2025, 2024 |
| Finland FIN | 3 | 25.3% | 2025, 2024 |
Coppedge, M. et al., V-Dem Dataset, Varieties of Democracy (V-Dem) Project
World Bank, World Development Indicators
Sources
Regime type
Regime type, Regimes of the World classification
V-Dem Institute, University of Gothenburg · via Our World in Data · CC BY 4.0 · updated annual
Four ranked categories, not a scale. It is the only such measure on this site. A closed autocracy holds no multiparty elections for its leader. An electoral autocracy holds them, but they are neither free nor fair. An electoral democracy clears that bar. A liberal democracy also has independent courts and protected personal freedoms. The four steps are not equal distances apart. So read the rank-based link, which uses only the order, rather than the ordinary one. Both are shown. The categories are set by cut-off points on the V-Dem indices already on this site. That is why its pairs with them are flagged as built from the same numbers. It is also why it is kept out of the governance score: a grouping of those indices averaged back in beside them would count each twice. Our World in Data extends the categories back to territories before independence. This site starts at 1960, and its single-year snapshot at 2010, so that extension reaches nothing shown here.
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 Regime type and Tax revenue
This page shows that two measures go together. It does not show that Regime type changes Tax revenue, or the reverse. These figures also describe countries, not individual people. See the ecological fallacy.
More links with Regime type or Tax revenue
- Regime type vs Rule of law before +0.69 → after adjusting +0.58
- Regime type vs Women's age at first marriage before +0.62 → after adjusting +0.50
- Political corruption vs Regime type before -0.64 → after adjusting -0.49
- Liberal democracy vs Tax revenue before +0.56 → after adjusting +0.48
- Electoral democracy vs Tax revenue before +0.56 → after adjusting +0.48
- Muslim share vs Regime type before -0.52 → after adjusting -0.47
- Free and fair elections vs Tax revenue before +0.54 → after adjusting +0.47
- Control of corruption vs Regime type before +0.62 → after adjusting +0.46