Caveat Emptor - When CPTED standards fail the test

Sherlock Holmes, the original evidence-based detective. He understood what professional standards require - verified facts, not confident claims.

by Gregory Saville

Caveat emptor: Let the buyer beware.

That warning exists for a reason. Professional standards are not casual suggestions. Cities rely on them to shape public investment and guide policy. A standard implies established evidence, professional consensus, and independent review. Without those foundations, the word “standard” is meaningless.

For years, I have seen, and helped create, CPTED standards by municipalities and governments. Most recently I read about so-called national CPTED standards. For practitioners and city officials unfamiliar with how standards are developed, such claims may appear credible. The language sounds authoritative. But standards are not created by declaration. They emerge through evidence and multidisciplinary collaboration.

CPTED has a long and well documented history. Since its early development in the 1970s, its principles have evolved through research, application, and field tests and they appear in peer reviewed studies, books, and professional publications.

Standards come from findings; findings come from verified evidence and data

For example, the International CPTED Association (ICA) has published a scientic CPTED bibliography documenting over 600 hundred studies. It also publishes The CPTED Journal, a peer reviewed scientific journal.


This is what professional legitimacy looks like. Evidence is published. Methods are documented. Claims are subject to independent review.

GLOBAL ISO STANDARDS 

Most recently, CPTED entered the International Organization for Standardization process. ISO standards are developed through rigorous evaluation by international technical committees representing multiple disciplines and countries. The global CPTED standard is ISO 22341:2021, and ICA experts helped draft the initial framework and later iterations adopted by ISO. For governments around the world, these standards provide developers, planners, and public officials with verified guidance grounded in scientific evidence and international professional consensus.

Standards do not originate from a private consulting firm presenting its own framework or a self-proclaimed expert at a conference. They emerge from broad professional review from experts, academics, and researchers with years of CPTED research and experience. And they do not gain legitimacy through branding or repetition. Their authority comes from the integrity of their development process.

This distinction is not theoretical. It has practical and legal consequences.

The first professional ISO CPTED standards by the International Standards Organization

A GLOBAL CPTED VOICE

The International CPTED Association publishes methodological guidance, including the CPTED Methodology White Paper, to ensure CPTED practice rests on evidence.


It publishes ICA guidebooks, professional training programs, and ISO standards about evidence via transparent and accountable processes. These resources reflect decades of collective work by practitioners and researchers worldwide.

They also show how CPTED is tested and verified. That is the foundation of any legitimate professional standard.

The stakes are significant. When a municipality or region adopts CPTED standards, it assumes those standards reflect the best available knowledge. But most government attorneys are not trained in CPTED or risk mitigation and cannot assess legitimacy of CPTED standards in their municipal policy. Some might assume their standards are grounded in research and recognized by the professional community, when they are not. That is an error with consequences for public safety, public investment, and public trust.

NASA advisor and astrophysicist Carl Sagan championed the Baloney Detection Kit - facts through evidence and data. Photo: Kenneth C. Zirkel, CC BY-SA 4.0, via Wikimedia Commons

THE BALONEY DETECTION KIT

Due diligence matters. Before adopting any CPTED standard, practitioners and clients should ask the simple questions once proposed by famed astrophysicist and NASA advisor, Professor Carl Sagan in his Baloney Detection Kit:

• How was it developed and tested (objective and independent?) 
• Who (and how many) reviewed it? 
• What evidence supports it? 
• Does it reflect the collective knowledge of the profession?

CPTED has matured into a global discipline because it remains grounded in evidence and professional accountability. If its standards carry weight, they only do so because they were earned through scientific validation and international recognition.

In CPTED, as in every serious profession, a standard cannot be declared. It must be demonstrated. Most important, a standard is not defined by who publishes it, but by who recognizes it. Caveat emptor still applies.