The first phase, involving 1,152 jailed bank robbers, examined the characteristics of the offenders' offenses. The second phase, with a sample of 2,107 bank robbers, examined factors leading to target choice and assessments of bank security. Results distinguished two groups. Amateurs directed their attention toward escape possibilities and the ability to oversee all parts of the inside of the bank. They felt they had planned inadequately or had no scenario for dealing with unforeseen events. Amateurs, unlike professionals, were little influenced by interior design and existing security. A majority of offenders developed an escape plan, and most planning focused on the steps in committing the robbery. About half did not know the likely punishment if caught, and being apprehended was seen largely as the result of insufficient planning rather than of police effectiveness. The amount of money expected from the offense was greatly overestimated. Results suggest that bank robbery prevention efforts should focus on those strategies that change the perceived opportunity structure of the offense. 2 references.