Five years ago, a landmark shift began in how the world thinks about interviewing during investigations and other information gathering. In May 2021, the Principles on Effective Interviewing for Investigations and Information Gathering, known as the Méndez Principles, were adopted, offering the global community a concrete, evidence-based alternative to coercive interrogation. As the Principles' own foreword observes, the interrogation of suspects is the most frequent setting in which torture and ill-treatment occur, often in the pursuit of confessions. Named after Professor Juan E. Méndez, former UN Special Rapporteur on Torture, the Principles emerged from a four-year collective, interdisciplinary effort by cross-regional experts in investigation, information gathering and human rights. They represent a decisive call to move away from harmful, unreliable interrogation methods and towards an approach on effective interviewing, grounded in science, law and ethics.
The impact is tangible. The Principles have been endorsed by UN General Assembly resolutions, cited by UN treaty bodies including the Committee Against Torture and embraced by regional mechanisms from the African Commission on Human and Peoples' Rights to the Organization of American States. They are now available in 24 languages, reaching practitioners in over 100 countries. Crucially, they have begun to change actual practice - across police services and criminal investigation bodies, prosecution offices, courts, oversight bodies and training academies spanning every region.
To mark this milestone, the APT - which supported the drafting process of the Méndez Principles, as well as their dissemination since their adoption and remains deeply committed to their implementation - is launching an online symposium: a series of blog articles and expert interviews that together take stock of five years of progress, examine the challenges that remain and look ahead to the next phase of implementation. Contributions come from members of the Steering Committee of Experts of the Méndez Principles, regional and thematic experts and practitioners working at the forefront of reform.
What This Series Will Cover
The online symposium unfolds across several interconnected blog articles and expert interviews, each approaching the fifth anniversary from a different angle. It brings together voices from practitioners and researchers to build a rounded picture of where the Méndez Principles stand today.
Experts will offer candid assessments of what has driven progress - and what has held it back - across different contexts. From institutional resistance within law enforcement to the persistent gap between legal frameworks and daily practice, these contributions address the realities of reform honestly and constructively.
The blog articles and expert interviews explore how the Principles have been received and applied in different parts of the world, and examine specific dimensions of implementation including legal and procedural safeguards and the institutional conditions for lasting reform.
This introductory article sets out the context for the series: what the Méndez Principles are and why they matter, and how the APT sees the path forward for their implementation.
What Is Effective Interviewing?
At their core, the Méndez Principles represent a paradigm shift: away from the assumption that coercion produces truth, and towards an understanding that effective interviewing is not only more ethical: it is more reliable.
Grounded in decades of scientific research, investigation and information gathering practice and international human rights law, the Principles propose a model of non-coercive interviewing built on rapport, open communication and respect for the dignity of the interviewee. This approach has consistently been shown to yield more accurate and usable information than coercive methods, which tend to produce false confessions, contaminated evidence and unsafe convictions.
Yet, as the Co-Chairs of the Steering Committee of Experts, Juan E. Méndez and Mark Thomson, have stressed in a statement issued in May 2025, it is important not to reduce the Principles to their rapport-building dimension alone. While this is central, the Co-Chairs insist that the integration of legal and procedural safeguards is equally integral to effective interviewing, not an add-on.
The Principles provide explicit guidance on how legal and procedural safeguards – such as access to lawyers, notification of third parties, the presumption of innocence and access to medical examinations - should be woven into the entire interviewing process. As the Co-Chairs explain, the term effective interviewing was chosen deliberately: it "builds rapport, prevents torture and ill-treatment, and upholds the legality of the questioning process."
The Méndez Principles are organised around six core principles – foundations, practice, vulnerability, training, accountability and implementation - all of which must be understood and applied together.
This holistic approach - addressing not just how to interview, but the institutional, legal, regulatory and oversight conditions that make effective interviewing sustainable - is what distinguishes the Méndez Principles from narrower reform efforts. It is designed, as the Co-Chairs underline, to help States shift questioning culture away from confession-driven practices and towards a more effective, just and fair administration of justice.
All resources, including the full text of the Principles in 24 languages, are available at interviewingprinciples.com.
How the APT Sees the Way Forward: Three Pillars of Implementation
Building on five years of experience across diverse national contexts, the APT, through an Implementation Guide to be released this month, has identified three interconnected pillars that underpin sustainable progress on the Méndez Principles. Implementation is not a linear process; these pillars often develop in parallel. But together, they offer a framework for durable, system-wide change.
Pillar 1 — Awareness and Acceptance
The foundation of any reform is knowledge. The Principles must be read, understood and accurately translated before they can be applied - and that understanding must reach well beyond a small community of specialists.
Dissemination must target all key actors in the justice ecosystem: law enforcement and their training academies, prosecution services, the judiciary, defence lawyers, oversight bodies, civil society, the media and academic institutions. But dissemination alone is not enough. Sustained awareness requires strong governance, including leadership that models expected standards, enforces compliance and holds officers accountable. Experience at the national level demonstrates the equal importance of investing in mid-level practitioners and emerging leaders, who often prove to be the most enduring agents of change.
Building momentum for reform demands deep engagement with all relevant stakeholders - not as a passive recipient of new guidelines, but as an active partner in change. Where institutional resistance arises, the scientific evidence underpinning non-coercive interviewing and its concrete operational benefits (reducing contested hearings, limiting complaints against investigators, decreasing the risk of unsafe convictions), can be powerful tools for persuasion.
Pillar 2 — National Ownership
Sustainable reform cannot be imported or imposed: it must be designed, driven and owned by national actors. This is perhaps the most important lesson of the first five years.
A meaningful starting point is national mapping: a systematic review of existing interviewing practices, legal frameworks and procedural safeguards. Such mapping must draw on perspectives from investigators and information gathering practitioners as much as from legal experts, and should pay particular attention to how the system responds to interviewees in situations of heightened vulnerability.
Legislative and regulatory reform is often the next step - whether that involves criminalising torture, strengthening criminal procedure codes, or introducing practice directions and disciplinary rules that can help translate legal guarantees into daily practice. Political champions within government, law enforcement and information gathering professionals are essential to ensuring new rules are respected in practice.
The judiciary has a critical role to play. Courts must rigorously exclude any evidence obtained through coercion, apply the law consistently, and hold responsible authorities to account. Too often, however, judges do not see it as their role to scrutinise interviewing practices. Strengthening judicial capacity and understanding of the science behind effective interviewing must become a much greater priority. Specialised training, bench books and judicial guidelines can help ensure interview integrity is consistently evaluated.
Training must be regular, systematic, and embedded in national curricula, not a one-off intervention, but a sustained investment in professional culture change. Experience has shown that training which is not deep enough to shift professional culture will struggle to hold under pressure. All justice actors — police, prosecutors, judges, and defence lawyers — should equally receive training on effective interviewing and safeguards.
Finally, monitoring and accountability are essential to verify that the Principles are being implemented rather than remaining aspirational. Oversight bodies — including national human rights institutions, national preventive mechanisms, civil society organisations, and internal police oversight units — all have a role to play. Increasingly, courts' application of the exclusionary rule - refusing to admit evidence obtained through coercion - is proving to be one of the most powerful accountability tools available.
Pillar 3 — Support from Partners
National actors, however committed, can still benefit from external support. The Méndez Principles were themselves the product of international, multidisciplinary collaboration and their implementation similarly benefits from sustained partnership.
Development partners, intergovernmental organisations, regional bodies and experienced NGOs can provide technical expertise, facilitate peer exchange, and connect reformers across countries who are navigating similar challenges. Civil society organisations are particularly valuable, bringing lived experience of the justice system that can inform national processes.
Effective partnerships must be long-term and genuinely grounded in respect for national ownership. Experience shows that early gains can regress without sustained commitment. Support that builds local capacity - rather than substituting it - is the most durable form of assistance.
Looking Ahead
The Méndez Principles have, in five years, achieved something remarkable: a genuine shift in global norms around effective interviewing. The breadth of international endorsement, the growth of national reform efforts, and the emergence of practitioner networks all testify to the momentum behind this initiative.
Yet the work is far from complete. In their May 2025 statement, Co-Chairs Juan E. Méndez and Mark Thomson called on everyone engaged with the Principles to "embrace their full scope and purpose, in order to help drive a transformative shift in mindsets and institutional cultures on investigations and information gathering." That call is the spirit in which this online symposium is offered. For many of the most vulnerable people passing through justice systems around the world, the protections the Principles enshrine remain out of reach. There is much still to do.
We invite you to read, share, and engage with the articles and interviews in this series — and to join the global community of practitioners, advocates and researchers working to make effective interviewing in line with the Méndez Principles the norm, not the exception.
The APT will soon be releasing an Implementation Guide to the Méndez Principles to support States and relevant stakeholders into national implementation along with a Toolkit for Defence Lawyers on their role in the implementation. For all resources, translations, and further information, visit interviewingprinciples.com and the APT's dedicated page on the Méndez Principles. Read the full statement by Co-Chairs Juan E. Méndez and Mark Thomson.
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