The fraud triangle

Most internal fraud is not committed by career criminals. It is committed by ordinary employees, often long serving and trusted, who cross a line under particular conditions. The classic model for understanding those conditions is the fraud triangle, developed from the work of criminologist Donald Cressey. It says that internal fraud typically needs three things to be present at once.

Pressure

Something pushes the person towards fraud. Often it is financial: personal debt, gambling, an addiction, a family crisis, or living beyond their means. It can also be workplace pressure, such as unrealistic targets, fear of redundancy, or a bonus that depends on hitting a number. The pressure is frequently something the person feels unable to share, which is why it stays invisible to colleagues.

Opportunity

The person must believe they can commit the fraud and get away with it. Opportunity comes from weak controls: one person handling a payment end to end, unreviewed access to systems, dormant supplier accounts nobody monitors, reconciliations that never happen, or a manager whose overrides are never questioned. Opportunity is the corner of the triangle an organisation can most directly control.

Rationalisation

Almost nobody thinks of themselves as a thief. People who commit fraud tell themselves a story that makes it acceptable: I'm only borrowing it and will pay it back, I deserve this after being passed over, everyone does it, the company can afford it, they owe me for all the unpaid overtime. Rationalisation is what lets an otherwise honest person live with what they are doing.

Why the model matters

The triangle explains why controls and culture both matter. Controls shrink opportunity. A fair, well led workplace reduces both pressure and the grievances that feed rationalisation. And it explains why "they would never do that" is not a control. Given enough pressure and a good enough story, people you like and trust can and do commit fraud. The honest answer to who might commit fraud here is: under the wrong conditions, almost anyone.