For the purpose of their studies, researchers must determine what specific behaviors qualify sex offenders as recidivists. They must decide whether only sex offenses will be considered, or whether the commission of any crime is sufficient to be classified as a recidivating offense. If recidivism is determined only by the commission of a subsequent sex offense, researchers must consider whether this includes felonies and misdemeanors. Answers to these fundamental questions will influence the level of observed recidivism in each study. Studies often vary in the length of time they monitor a group of sex offenders in the community. Ideally, all individuals in any given study should have the same length of time "at risk" and thus equal opportunity to commit subsequent offenses. In practice, however, this almost never happens. This problem is addressed by using survival analysis, a methodology that takes into account the amount of time every subject has been in the community, rather than a simple percentage. The identification of risk factors that may be associated with recidivism of sex offenders can aid practitioners in devising management strategies that best protect the community and reduce the likelihood of further victimization. This paper provides guidelines for determining such factors. Understanding the concept of "base rates" is also essential when studying sex offender recidivism. A base rate is simply the overall rate of recidivism of an entire group of offenders. If the base rate for an entire group is known, then without other information, practitioners can predict that any individual in this group has a chance of recidivating.