This paper offers one of the first economic analyses of scams. Its major finding is that, unlike other crimes, imperfect enforcement may increase victimization by deterring only low-ability scammers whose failed attempts would otherwise alert potential victims before encounters with high-ability...

We model deterrence with costly punishment when criminals have different abilities. Abilities are unobserved by both criminals and the courts. Based on past successes, criminals update their priors on being high-ability criminals. Courts cannot observe a criminal’s total past offenses. They do...