This year marks a remarkable milestone: the 25th anniversary of the World Prison Brief. What began as a modest attempt to compile worldwide prison data has evolved into an indispensable resource accessed over 2.7 million times by more than 524,000 users from 230 countries and territories in 2025 alone.
How It All Began
The late 1990s presented a clear challenge for criminal justice researchers and policymakers: while various organisations collected prison data, there was no comprehensive worldwide overview. The United Nations had begun conducting periodic crime surveys in the 1970s, including prison population information, but response rates were disappointing and data reliability varied considerably. The Council of Europe had started gathering prison statistics from member states in 1983, and the UN Latin America Institute was reviewing prison populations across Latin America and the Caribbean. Since 1993, the Asian and Pacific Conference of Correctional Administrators had been collecting data from approximately twenty countries attending their annual conferences.
These important initiatives laid the groundwork, but what was needed was a unified approach that could construct a truly global picture. By assembling all traceable data, it became possible to create the first World Prison Population List, featuring figures for 180 countries, which the Home Office published in early 1999.
A more comprehensive resource was required, which could track not just overall numbers, but detailed breakdowns of prison populations. Roy Walmsley, the founder of the World Prison Brief, recalls: ‘Andrew Coyle at the International Centre for Prison Studies offered me the opportunity to do exactly this. And in September 2000, the World Prison Brief was launched.’ The World Prison Population List, published in 1999, served as the precursor to what would become a much more comprehensive resource. As Walmsley notes, ‘In the years since it has expanded further and now provides details of prison population levels in over 220 independent countries and dependent territories.’
Professor Andrew Coyle CMG, inaugural director of the International Centre for Prison Studies, reflects on the transformation he helped set in motion:
Over the past 25 years, the World Prison Brief has evolved from a pioneering online database to become the world’s leading source for comparative prison information. What began as a simple ambition to provide practitioners and academics with reliable prison statistics has grown into an indispensable resource that informs human rights discourse, shapes evidence-based policy, and promotes transparency in prison systems worldwide. The World Prison Brief’s enduring impact lies not just in the data it provides, but in its contribution to better-informed discussions about the appropriate use of imprisonment.
Purpose and vision
The World Prison Brief was conceived with a clear mission in mind. As Roy Walmsley explains:
The main aim of the World Prison Brief is to enable countries to think about their use of imprisonment in the knowledge of how it compares with that of other countries around the world, and in particular their immediate neighbours. By facilitating evidence-based discussion on the use of imprisonment around the world, the intention is to improve decision-making in accordance with international human rights standards. It is hoped that this may lead to more economical use of imprisonment, given the high costs involved and the disputed effectiveness of this type of punishment.
This vision recognises that meaningful prison reform requires context and comparison. While prison management, including the appropriateness of prison population levels, should ultimately be judged against ‘injunctive norms’—according to principles such as international human rights standards—rather than simply comparing one country against another, the reality is that countries are naturally curious about their standing relative to others and actively look to see how their approaches compare. These ‘descriptive norms’—actual practice across different countries—serve a key purpose: they can highlight outliers, prompt questions as to why certain approaches differ so dramatically, and encourage countries to examine whether their practices align with international standards. Understanding how their approaches compare with those of other nations, particularly their regional neighbours, provides valuable context for policy discussions and can illuminate alternative approaches that may be more effective or more humane.
Evolution and current scope
Today’s World Prison Brief extends far beyond its original scope. While the initial focus was on overall prison population levels, the resource now includes crucial breakdowns showing the number of pre-trial prisoners, women, juveniles, and foreign prisoners in each country’s system. Occupancy levels provide insights into overcrowding—a persistent challenge in many countries worldwide.
The database features comprehensive ‘highest to lowest’ rankings, allowing users to see precisely where each country stands regarding prison population levels and the proportion of different prisoner categories. Information about trends in prison populations has been added, along with details about the prison administration in each country.
The work behind the database
The World Prison Brief’s monthly updates represent a considerable undertaking, and its continued existence and growth depend on effective knowledge transfer between generations of researchers. Helen Fair, Lead Researcher on the World Prison Brief, has been meticulously tracking prison population levels for over ten years, and since 2021 she has taken full responsibility for the resource. This successful handover from founder Roy Walmsley ensured the database’s sustainability and continued development. Under Helen’s leadership, the resource has maintained its rigorous standards while adapting to new challenges and expanding its reach to serve an ever-growing global user base.
The data collection process is both comprehensive and challenging. Figures originate primarily from national prison administrations through various channels: some countries maintain prison administration websites holding population data, others publish annual reports, and some provide information via their responsible ministries or national statistical offices. International surveys conducted by the United Nations, regional conferences, the Council of Europe, and the US State Department for human rights country reports also provide valuable data sources. For countries that do not regularly publish official data, we rely on direct contact with prison administrations while carefully monitoring newspaper reports and international news coverage featuring statements by senior officials. The World Prison Brief works exclusively with official figures, understanding that their reliability ultimately depends on the accuracy of the source data. New figures undergo verification against historical patterns, and questionable data is excluded from the database.
Real-world impact and recognition: voices from the field
The impact of the World Prison Brief extends far beyond academic circles. Countries increasingly reference these comparative data in policy discussions, recognising the value of understanding their position within the global context. The database’s influence can be traced through government reports, prison administration annual publications, NGO advocacy work, academic research, and media coverage.
The value of the World Prison Brief is perhaps best expressed by those who rely on it in their professional work. Zaved Mahmood, who leads work on detention and incarceration at the Office of the United Nations High Commissioner for Human Rights, emphasises the human dimension of the data:
Data is fundamental to our human rights work on incarceration. All data tells us a story. Prison statistics are not simply numeric;behind them, there are always human faces. The UN Common Position on Incarceration specifically emphasised the critical importance of robust data for strengthening programming and research capacity. In this regard, the World Prison Brief has proven an extremely useful resource, especially considering the current lack of a unified global information hub on prison systems.
In academia, the resource has become an indispensable teaching tool. Dr Mary Rogan, Professor in Law and Fellow at Trinity College Dublin’s School of Law, describes its classroom impact:
I use the World Prison Brief with my students of Penology and Human Rights and Deprivation of Liberty at the School of Law, Trinity College, Dublin almost every week. It is an invaluable resource allowing us to see at a glance differences and similarities across countries. We examine reasons for the differences we see and explore changes over time. The amount of work which goes into making such an easy to use, accessible and helpful database is immense and Helen Fair and the team working with her are doing an immense service to all of us.
Dr Rogan’s further reflection captures the deeper significance of the work:
The World Prison Brief provides important and accurate information from around the world, but, even more fundamentally, it provides a portal through which we can see how the state’s power to punish is being used. This bearing witness work, and the knowledge-generation it permits, is of immense moral importance.
The database’s influence extends into journalism. Sarah Johnson, writing for The Guardian, featured the World Prison Brief in two Guardian articles examining women in prison globally and the rising global crisis of women’s imprisonment. She reflects on the database’s journalistic value:
The World Female Imprisonment List has been vital in reporting on women in prison globally for the Guardian. I have used it to illustrate that the numbers of women in prison are going up all over the world and to underline that it is an issue that needs and merits attention. I can only hope that it expands to reveal more injustices faced by women, many of whom are forgotten while they languish in prisons.
Looking ahead
As the World Prison Brief enters its second quarter-century, its role becomes ever more crucial. In an era of fake news and misinformation, reliable, verified data sources like the World Prison Brief are more important than ever, providing trustworthy information in a landscape where data integrity cannot be taken for granted.
The resource continues to evolve to meet these challenges, adapting to new data sources and user needs while maintaining the rigorous standards that have made it a trusted global reference. Currently, it is undergoing a major facelift that will give users more scope to filter data, compare countries and regions, and visualise trends over time, providing even greater flexibility and utility. ICPR is extremely grateful to our donors for providing funding for this significant enhancement. Securing funding for existing databases can be particularly challenging, making this support all the more valuable.
As countries grapple with questions of prison reform, non-custodial alternatives, and criminal justice effectiveness, this resource remains an essential tool for informed decision-making. After a quarter-century, it stands as a testament to the power of systematic data collection and the importance of addressing shared challenges. In providing this crucial service to the global community, ICPR is committed to continuing the vital work of bearing witness to how societies choose to exercise their power to punish, enabling more thoughtful, humane, and effective approaches to criminal justice worldwide.