Using data corrected for victim underreporting, crime supply functions are reestimated in this paper. Underreporting is found in both a mean-variance specification and a conventional crime supply function that includes measures of the offender's gains and losses involved in property crimes that certainty and severity of punishment still deter. When underreporting is corrected, increases in prison admission rates and prison sentences continue to have a negative effect on the rates of robbery, burglary, larceny and auto theft. It is cautioned, however, that this seeming support for the "deterrence hypothesis" must be balanced against the strong evidence that improved legitimate opportunities also have a negative effect on crime. It is concluded, based on the use of improved crime data and a more intuitive economic specification of the offense supply function, that higher income is a better deterrent to some crimes than increased punishment. (Author/GC)