Do Interpersonal trust and Public social spending go together across countries?

Across 40 countries the link before adjusting for anything is r = +0.45, on a scale from -1 (opposite) to +1 (in step). A version that uses only each country's rank gives +0.41.

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

There are not enough years of data within countries to check this over time.

Does Interpersonal trust cause Public social spending?

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.

Interpersonal trust vs. Public social spending

Holds up after adjusting for income

Across 40 countries, Interpersonal trust and Public social spending rise and fall together at r = +0.45 (on a scale from −1 to +1, where 0 means no link). Comparing only countries with similar income (GDP per person) shrinks it to +0.22 (q = 0.017, allowing for the many pairs tested). Much of the first figure is that both measures rise with national income, but a weak positive link remains. Caution: leave-one-out range spans 0.17 in r.

Comparing countries across the middle half of interpersonal trust, 20.5% to 47.2% of respondents, public social spending is 3.64% of GDP higher at the top of that range than the bottom. Comparing only countries with similar national income, the gap is 2.17% of GDP.

Link before adjusting (r)+0.447p = 0.004 · 40 countries

After adjusting for national income+0.216p = 0.187 · likely range [-0.11, +0.50]

p, allowing for regions0.001standard error 0.015 · 4 regions

Check for luck (q)0.017across 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.

Interpersonal trust · % of respondentslink with income +0.66 · high

Public social spending · % of GDPlink with income +0.44 · 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	+0.447	0.004	40
By rank (Spearman), not adjusted	+0.406	0.009	40
Standard (Pearson), adjusted for national income	+0.216	0.187	40
By rank (Spearman), adjusted for national income	+0.163	0.322	40

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 40 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: +0.231 (a minus sign means it grew).

How solid is it?

Leaving out one country at a time, r ranges from +0.091 (without IRL) to +0.264 (without FRA). 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: IRL (-0.125).

Fragile: this link may not hold up.

leave-one-out range spans 0.17 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
Europe & Central Asia	30	+0.27

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	14	-0.28
Middle third	13	+0.26
Richest third	13	-0.07

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	34	+0.19

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 = +0.216 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 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

	% of respondents	% of GDP	Years
Denmark DNK	73.9%	26.4%	2022, 2024
Norway NOR	72.1%	24.1%	2022, 2024
Finland FIN	68.4%	31.4%	2022, 2024
Sweden SWE	62.8%	26.1%	2022, 2024
Iceland ISL	62.3%	19.2%	2022, 2024
Switzerland CHE	58.5%	16%	2022, 2024
Netherlands NLD	57%	18.9%	2022, 2024
New Zealand NZL	56.6%	24.6%	2022
Austria AUT	49.8%	31.6%	2022, 2024
Australia AUS	48.5%	17.1%	2022
Canada CAN	46.7%	19.3%	2022
United Kingdom GBR	43.3%	23%	2022, 2023
Germany DEU	41.6%	27.9%	2022, 2024
Spain ESP	41%	25.9%	2022, 2024
Ireland IRL	37.3%	14.4%	2010, 2024

Haerpfer, C. et al., World Values Survey; EVS, European Values Study
OECD databases as named on each indicator: PISA, Social Expenditure Database (SOCX), Income Distribution Database, Development Assistance Committee statistics, Family Database, Government at a Glance, Corporate Tax Statistics, employment and environment statistics

Sources

Interpersonal trust

Share agreeing that most people can be trusted

World Values Survey Association and European Values Study · via Our World in Data · Free for non-commercial use with attribution · updated irregular (survey waves, roughly every 5 years)

The share who answer "most people can be trusted" rather than "you can't be too careful". Trust in other people is the classic measure of social ties (social capital). It is only loosely linked to national income. That makes it one of the few measures here where adjusting for GDP is a real test, not a foregone result. The survey runs in waves, not every year. So data for each country are sparse and uneven, and two readings for a country may be five or more years apart.

Public social spending

Public social expenditure

OECD · via Our World in Data · CC BY 4.0 (OECD terms and conditions) · updated annual, except the snapshots noted per indicator · comparable from 1980 only

All public social spending, as a share of GDP: pensions, health, family, unemployment, housing and the rest. The figures before 1980 are stitched together from older OECD tables and from Lindert's historical estimates, so they are left out. The OECD's social spending database (SOCX) itself starts in 1980. The four spending areas below are parts of this total and are flagged as such.

How this was computed

Data used: most recent value in 2010-2025; values come from 2010–2024. 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 4 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 Interpersonal trust and Public social spending

This page shows that two measures go together. It does not show that Interpersonal trust changes Public social spending, or the reverse. These figures also describe countries, not individual people. See the ecological fallacy.