Across 168 countries, Ease of forming a party and Environment score rise and fall together at r = +0.32 (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 = +0.39, q = 0.037, allowing for the many pairs tested).
Comparing countries across the middle half of ease of forming a party, 0.321 to 2.13 points, environment score is better by 0.213 typical gaps at the top of that range than the bottom. Comparing only countries with similar national income, the gap is 0.254 typical gaps.
Link before adjusting (r)+0.325p = 1.7e-5 · 168 countries
After adjusting for national income+0.391p = 1.7e-7 · likely range [+0.25, +0.51]
p, allowing for regions0.003standard error 0.083 · 7 regions
Check for luck (q)0.037across 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
Environment score · typical gaps (standard deviations)link 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
+0.325
1.7e-5
168
By rank (Spearman), not adjusted
+0.268
0.000
168
Standard (Pearson), adjusted for national income
+0.391
1.7e-7
168
By rank (Spearman), adjusted for national income
+0.385
2.8e-7
168
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 168 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: -0.067 (a minus sign means it grew).
How solid is it?
Leaving out one country at a time, r ranges from +0.375 (without QAT) to +0.409 (without HKG). 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: HKG (+0.018).
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
21
+0.30
Europe & Central Asia
48
+0.46
Latin America & Caribbean
23
-0.00
Middle East, North Africa, Afghanistan & Pakistan
22
+0.29
Sub-Saharan Africa
46
+0.13
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
56
+0.31
Middle third
56
+0.30
Richest third
56
+0.54
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
99
+0.08
Muslims
48
+0.33
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
25
+0.19
Never a European colony
21
+0.73
Spain
19
-0.01
United Kingdom
49
+0.34
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
25
+0.30
No strong official ideology
116
+0.38
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
26
+0.29
No parties banned
121
+0.18
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 = +0.311 after dropping 8 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
score (higher = fewer barriers)
typical gaps (standard deviations)
Years
United States USA
2.95
-0.491
2025, 2024
Costa Rica CRI
2.81
0.544
2025, 2024
Sweden SWE
2.76
0.257
2025, 2024
Argentina ARG
2.75
-0.619
2025, 2024
Belgium BEL
2.72
-0.458
2025, 2024
Austria AUT
2.68
0.246
2025, 2024
Italy ITA
2.66
-0.13
2025, 2024
United Kingdom GBR
2.65
-0.167
2025, 2024
Switzerland CHE
2.63
-0.314
2025, 2024
South Africa ZAF
2.6
-0.667
2025, 2024
Trinidad and Tobago TTO
2.57
0.0462
2025, 2024
Denmark DNK
2.53
-0.462
2025, 2024
Cyprus CYP
2.51
0.125
2025, 2024
Sri Lanka LKA
2.5
0.377
2025, 2024
Japan JPN
2.48
0.488
2025, 2024
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. wdi
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.
PlaceStats · via PlaceStats · Derived work; each member keeps its own licence · updated recomputed with the panel
The average of 3 measures from 1 publisher. Each measure is first put on a common scale: 0 is the average country in an average year, and 1 is a typical gap between countries (a standard deviation). Each is turned so that higher is better. Measures are averaged within each publisher first, so a publisher with many measures does not count for more. Members: Forest area, CO2 per capita, Protected land.
How this was computed
Data used: most recent value in 2010-2025; values come from 2024–2025. 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 Environment score
This page shows that two measures go together. It does not show that Ease of forming a party changes Environment score, or the reverse. These figures also describe countries, not individual people. See the ecological fallacy.
More links with Ease of forming a party or Environment score