Ease of forming a party vs. Military spending
Holds up after adjusting for income
Across 157 countries, Ease of forming a party and Military spending rise and fall together at r = -0.19 (on a scale from −1 to +1, where 0 means no link). It holds up almost unchanged when only countries with similar income (GDP per person) are compared (r = -0.21, q = 0.021, allowing for the many pairs tested). Caution: leave-one-out range spans 0.24 in r.
Comparing countries across the middle half of ease of forming a party, 0.336 to 2.16 points, military spending is 0.783% of GDP lower at the top of that range than the bottom. Comparing only countries with similar national income, the gap is 0.906% of GDP.
Link before adjusting (r)-0.188p = 0.018 · 157 countries
After adjusting for national income-0.214p = 0.007 · likely range [-0.36, -0.06]
p, allowing for regions0.001standard error 0.037 · 7 regions
Check for luck (q)0.021across 17,292 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.
Ease of forming a party · score (higher = fewer barriers)link with income +0.38 · moderate
Military spending · % of GDPlink with income +0.20 · independent
“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 | -0.188 | 0.018 | 157 |
| By rank (Spearman), not adjusted | -0.234 | 0.003 | 157 |
| Standard (Pearson), adjusted for national income | -0.214 | 0.007 | 157 |
| By rank (Spearman), adjusted for national income | -0.345 | 1.1e-5 | 157 |
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 157 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: -0.025 (a minus sign means it grew).
How solid is it?
Leaving out one country at a time, r ranges from -0.434 (without UKR) to -0.196 (without SAU). 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: UKR (-0.220).
Fragile: this link may not hold up.
- leave-one-out range spans 0.24 in r
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 | 18 | -0.26 | |
| Europe & Central Asia | 48 | -0.05 | |
| Latin America & Caribbean | 21 | -0.02 | |
| Middle East, North Africa, Afghanistan & Pakistan | 20 | -0.22 | |
| Sub-Saharan Africa | 44 | -0.32 |
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 | 53 | -0.34 | |
| Middle third | 52 | -0.09 | |
| Richest third | 52 | -0.65 |
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 | 94 | -0.12 | |
| Muslims | 44 | -0.51 |
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 | 23 | -0.21 | |
| Never a European colony | 20 | -0.38 | |
| Spain | 19 | +0.15 | |
| United Kingdom | 45 | -0.51 |
By official ideology
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 | ||
|---|---|---|---|
| Nationalist | 22 | -0.63 | |
| No strong official ideology | 110 | -0.18 |
By party system
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 | ||
|---|---|---|---|
| A few parties banned | 24 | +0.12 | |
| No parties banned | 114 | -0.29 |
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 = -0.174 after dropping 15 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.
Loading…
Over time, within countries
Everything above compares countries with each other at one moment. This section compares each country only with itself over 36years. 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 = -0.041, 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 ease of forming a party moved did not tend to see their military spending move with it.
Across countries (adjusted)-0.214for comparison
Within countries-0.092each country vs itself
…and vs the same year elsewhere-0.041q = 0.428 · 164 countries
Year-on-year changes-0.020q = 0.292
5,262 country-years (one country in one year), 164 countries, 1990–2025, about 32 years each on average. Share of the variation that happens within countries over time: 12% for Ease of forming a party, 56% for Military spending. 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): -0.041. 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
score (higher = fewer barriers) | % of GDP | Years | |
|---|---|---|---|
| United States USA | 2.95 | 3.12% | 2025 |
| Costa Rica CRI | 2.81 | 0% | 2025 |
| Sweden SWE | 2.76 | 2.47% | 2025 |
| Argentina ARG | 2.75 | 0.563% | 2025 |
| Belgium BEL | 2.72 | 2.01% | 2025 |
| Austria AUT | 2.68 | 1.1% | 2025 |
| Italy ITA | 2.66 | 1.89% | 2025 |
| United Kingdom GBR | 2.65 | 2.35% | 2025 |
| Switzerland CHE | 2.63 | 0.757% | 2025 |
| South Africa ZAF | 2.6 | 0.737% | 2025 |
| Trinidad and Tobago TTO | 2.57 | 0.939% | 2025 |
| Denmark DNK | 2.53 | 3.25% | 2025 |
| Cyprus CYP | 2.51 | 1.61% | 2025 |
| Sri Lanka LKA | 2.5 | 1.31% | 2025 |
| Japan JPN | 2.48 | 1.41% | 2025 |
Coppedge, M. et al., V-Dem Dataset v16, Varieties of Democracy (V-Dem) Project; Lindberg, S. I. et al., Varieties of Party Identity and Organization (V-Party) Dataset. Read from the V-Dem Institute's vdemdata package.
World Bank, World Development Indicators
Sources
Ease of forming a party
Barriers to forming a party (higher = fewer barriers)
V-Dem Institute, University of Gothenburg · CC BY-SA 4.0 · updated annual (V-Dem); V-Party per election, to 2019
How hard is it to start a new party? Experts answer from 0 ("parties are not allowed") to 4 ("no substantial barriers"), counting both legal hurdles such as deposits and membership rules and harassment of party leaders. V-Dem turns the answers into a score of about -4 to +4. A part of V-Dem's freedom of association index.
Military spending
Military expenditure (% of GDP)
Stockholm International Peace Research Institute (SIPRI) · 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 17,292 pairs at once, using the Benjamini–Hochberg method. Underlying data last updated V-Dem v16; V-Party v2. How the country data works · explore Ease of forming a party and Military spending
This page shows that two measures go together. It does not show that Ease of forming a party changes Military spending, or the reverse. These figures also describe countries, not individual people. See the ecological fallacy.
More links with Ease of forming a party or Military spending
- Ease of forming a party vs Freedom of expression before +0.86 → after adjusting +0.85
- Ease of forming a party vs Political rights (FH) before -0.78 → after adjusting -0.80
- Civil liberties (FH) vs Ease of forming a party before -0.76 → after adjusting -0.78
- Ease of forming a party vs Voice and accountability before +0.73 → after adjusting +0.78
- Civil society participation vs Ease of forming a party before +0.78 → after adjusting +0.77
- Ease of forming a party vs Women's political empowerment before +0.73 → after adjusting +0.73
- Ease of forming a party vs Free and fair elections before +0.69 → after adjusting +0.71
- Ease of forming a party vs Economy free of state ownership before +0.67 → after adjusting +0.66