According to Donald R. Cressey, president-emeritus of the Association of Certified Fraud Examiners, the three factors contributing to a person committing fraud are:

(1) Pressure/Motivation, (2) Rationalization, and (3) Opportunity 
​Below are examples of each factor
Pressure
  • High levels of debt
  • Gambling addiction
  • Living beyond means
Rationalization
  • Just "borrowing" it
  • I've earned it
  • Everyone has done it
Opportunity
  • Person is trusted
  • Weak internal controls
  • Has access to funds