Prison as a Criminal School:

We investigate peer effects on crime-specific recidivism using register data for the entire Danish prison population. We find that inmates strengthen criminal capital in prison due to exposure to offenders with the same field of specialisation (reinforcing peer effects). Our results accord with a theory of crime-specific knowledge transmission and network building: we find reinforcing peer effects for crimes that require specific capital, planning and network (e.g. drug crimes, theft, burglary and fencing) and/or are more effective when committed in groups (e.g. threats and vandalism). Effects are especially strong due to exposure to more experienced criminals and dropouts.