For much of history, forced labor was widespread and brutal. Tens of millions of people were made to work under the threat of violence or punishment. At its most extreme, this meant slavery: people were bought, sold, and inherited like property.

These abuses weren’t hidden from the state. Governments often allowed forced labor, protected slave owners by law and through force, and used forced labor themselves. Most people saw slavery and forced labor as a normal part of economic and social life.

The situation today is very different. Many governments have ended their own use of forced labor, changed laws, and now prosecute those who use it. As we explain below, some forms of forced labor and human trafficking still exist — but they are much less common than in the past. Most people now see them as abhorrent, and they expect governments to protect people from them.

The chart below summarizes how these massive changes unfolded across the globe. It shows for each point in time how many countries had not yet abolished “large-scale” forced labor, meaning forced labor that was common and entrenched — tolerated, enabled, or imposed by authorities, rather than isolated abuse.¹

To measure this specific form of large-scale forced labor, we rely on expert assessments from the Varieties of Democracy (V-Dem) project, based at the University of Gothenburg, in Sweden.² Below, we explain the precise definitions in more detail, and say more about why we chose this source and how we built on it.

What the chart shows has been well documented in the many excellent books by historians and social scientists. They discuss in rich and horrific detail how these oppressive systems worked, and how enslaved people and abolitionists fought to bring them down.³ What we add to this is a quantitative, bird’s-eye perspective on the global history of slavery and forced labor.

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In this chart, we see how common large-scale forced labor was until recently. Based on this data, just nine countries did not have large-scale forced labor at any time since the late 18th century.⁴

After a small number of countries reduced forced labor substantially in the early 1800s, the rest of the 19th century, and the first decades of the 20th, saw steady successes in the fight for abolition.

Progress accelerated in the mid-20th century. In just a few decades, dozens of countries abolished large-scale forced labor: at the end of World War II, almost 100 countries still had such systems in place. Only one generation later, by 1975, that number had fallen to 31. In recent decades, the number of countries where forced labor is common has continued to fall, though at a slower pace.

In 2024, there were nine countries with large-scale forced labor.⁵ And even in countries where forced labor was not common and entrenched that year, there were cases of it in every one of them.

While forced labor remains a problem today, its decline is one of the biggest social and economic changes in history. It greatly reduced some of the worst abuses of human rights and gave many millions of people much more freedom to live their lives. This shows that large changes to our societies and economies are possible — even those that were once unimaginable.

Much of this progress is also surprisingly recent. In many places, slavery was abolished in the 19th century, but similarly repressive systems continued under new names and legal systems. It wasn’t until the decades after World War II that decolonization dismantled the highly coercive colonial labor systems in many more countries.

Summarizing changes of this scale in a single chart is challenging. Forced labor can take many different forms; legal rules and real-world practices often don’t match, and no country is completely free from forced labor. So, in the rest of the article, we explain these measurement challenges, describe how the expert assessments from V-Dem approach them, and detail how we constructed the chart.

What makes forced labor difficult to track

To create a chart that gives a global perspective on the history of slavery and forced labor, we had to confront several major data challenges.

First, even though people broadly agree on what it is, forced labor can take many forms. It is often understood as a person being unable to quit a job because they face coercion by their employer. But beyond that, forced labor comes in many shapes.

The person might be forced to work because they are legally treated as property (often called chattel slavery, or simply slavery), because they are pressured to repay a loan with unfair or unclear terms (debt bondage), or because their employer takes away crucial documents, such as an ID or passport. This can happen in many parts of the economy — agriculture, mining, construction, domestic work (often called domestic servitude), or the sex trade. The coercion might be done by an individual, a business, or the state.

These differences make it difficult to track forced labor consistently across countries and over time.

Second, legal rules and real-world practices often do not match. A government may ban forced labor on paper, but it might be unable, or unwilling, to enforce the ban. And sometimes the opposite is true: forced labor can be rare even if a country’s laws do not explicitly protect people from it.

For this reason, looking only at what the law says can miss what matters most: whether forced labor was actually rare in practice.⁶

Third, no country is completely free of forced labor. It is not a simple divide where some countries have it and others do not. This is also true today — there are cases in every country.

But if we treat countries with rare cases the same as countries with large forced labor systems, we miss important differences in how many people suffer and how governments see forced labor. At the same time, if we focus only on the most extreme cases of slavery in the past, we understate how serious the problem remains today.

As a result, the challenge is determining where to draw the line between countries that have large-scale systems of slavery and forced labor, and those where they are much rarer.

We relied on data from expert surveys collected by the Varieties of Democracy project to address these challenges.

What data we used

We used data from the Varieties of Democracy project (V-Dem), which relies on surveys of around 3,500 country experts, and is based at the University of Gothenburg in Sweden.⁷

V-Dem’s expert surveys include two questions on forced labor: one asks about how free men are from servitude and other forms of forced labor, and the other asks the same for women. Experts score each country on a scale from 0 to 4. A score of 0 corresponds to forced labor being widespread and being accepted or organized by the state; a score of 4 corresponds to forced labor being virtually non-existent.⁸

V-Dem takes the independent expert assessments and calculates an overall score. They do this by using a statistical model that combines the individual expert scores while accounting for uncertainty and differences between the individual assessments.⁹

This approach helps address the key measurement challenges mentioned above: using country experts helps measure what forced labor looks like in practice — not just what the law says. Asking the experts to rate forced labor on a scale recognizes that it exists everywhere, but at different levels. And the fact that each point on the scale comes with a clear description helps experts interpret the scores in a similar way, and makes different forms of forced labor more comparable across places and over time.

Despite these strengths, V-Dem also has limitations that matter for our purposes here.¹⁰

First, its forced-labor indicators are designed to measure severity, not to draw a clear line between countries with and without large-scale forced labor. V-Dem’s main measure places countries on a continuous scale, and a secondary measure places them on the original 0-4 scale. But neither specifies where a meaningful cutoff for “large-scale” forced labor should lie.

Second, coverage is incomplete. Some of today’s smaller countries are not included in V-Dem at all. Others are only covered from independence or from around 1900 onward¹¹, and for a few country-years, the forced-labor assessment data are missing.

To address these limitations, we built on V-Dem’s work in two ways. We set a cutoff for what counts as “large-scale” forced labor, and we extended coverage where possible by linking modern countries to earlier states that governed the same territory.

In a small number of cases where this was not possible, we consulted additional sources. Throughout, we took a conservative approach and never altered V-Dem’s own assessments. We explain this process in detail in the next sections.

How we built on V-Dem’s data

To get from V-Dem’s scores to how many countries had yet to abolish large-scale forced labor, we first had to choose a cutoff on V-Dem’s scale for what counts as “large-scale”.

We counted a country as having large-scale forced labor if V-Dem’s aggregate score on the original 0–4 scale, for either men or women, was 0 (forced labor was widespread and accepted or organized by the state) or 1 (forced labor was substantial and the state either unable or unwilling to contain it).

We did not count a country as having large-scale forced labor if the overall scores for men and women were 2, 3, or 4. This means cases where forced labor was at most tolerated in some areas or among some social groups (score of 2), infrequent and sincerely opposed by the state (score of 3), or virtually non-existent (score of 4).

We chose this cutoff because we think it strikes a balance between capturing the big differences between historical and current forms of slavery and forced labor, and acknowledging that forced labor was common in many countries until relatively recently, and is common in some countries to this day.

This cutoff also lines up reasonably well with how major historical changes are commonly understood. For example, it places the end of large-scale forced labor in the United States at the end of the Civil War, and in the Soviet Union at the disbanding of the Gulag system after Stalin’s death. At the same time, it identifies prominent recent cases where forced labor remains widespread, such as Afghanistan and North Korea.

Wherever one draws the line, there will always be borderline cases. For example, the cutoff makes 1979 the year China eliminated large-scale forced labor, when its forced labor system was weakened after Mao’s death. But it would also be reasonable to argue that large-scale forced labor still exists in China today, given reports that the government forces parts of the country’s minority populations, especially the Uyghurs, to work. Still, changing the cutoff to include all these targeted cases of forced labor (score of 2) does not change the overall trend of a large decline in forced labor.

How we filled the gaps in V-Dem’s historical coverage

V-Dem’s data does not cover every country for all of the last two centuries. To build a continuous series starting from today’s countries, we extended the data back in time where we could. We kept V-Dem’s expert assessments unchanged and relied on V-Dem’s own historical coverage wherever possible. Only when there was no way to do that did we conservatively draw on additional sources.

V-Dem’s coverage is enough to identify an end year for large-scale forced labor in 112 countries using our cutoff. For the remaining 62 countries, V-Dem’s coverage starts later — often because these countries were not independent states for the full period we cover. To include these countries in a consistent long-run global series, we extended coverage back in time.

Where a modern country’s territory was previously governed by an identifiable predecessor state, we applied the predecessor’s end year.¹² This allowed us to assign end years for another 39 countries. For example, Belarus is covered only from 1990, but was part of the Soviet Union, so we use the Soviet Union’s end year of 1954.

For the remaining 23 countries without clear historical predecessors, we consulted additional sources to manually fill the gaps ourselves. Where sources were unclear or disagreed, we adopted the conservative assumption that large-scale forced labor continued until the first year V-Dem covers the country. For example, the additional sources are unclear about the extent of forced labor in Nigeria in the early 20th century, which is why we use 1913 as the end year, the year before the V-Dem starts (and there’s no large-scale forced labor based on the expert assessments and our cutoff).

And where data was missing for only a few years, we assumed there was no abrupt change. For instance, there is a two-year gap for Jordan in 1921 and 1922, when it wasn’t a part of the Ottoman Empire anymore, but it isn’t included by V-Dem on its own yet.

You can find the end year for every country, as well as short notes explaining how we decided on each of them, in our country-by-country table.¹³

Bastian Herre, Esteban Ortiz-Ospina, and Max Roser (2026) - “Tracking historical progress against slavery and forced labor: a long-run data view” Published online at OurWorldinData.org. Retrieved from: 'https://data-wdi-depsupdate.owid.pages.dev:8789/20260223-064745/slavery.html' [Online Resource] (archived on February 23, 2026).

@article{owid-slavery,
    author = {Bastian Herre and Esteban Ortiz-Ospina and Max Roser},
    title = {Tracking historical progress against slavery and forced labor: a long-run data view},
    journal = {Our World in Data},
    year = {2026},
    note = {https://data-wdi-depsupdate.owid.pages.dev:8789/20260223-064745/slavery.html}
}

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