Date of Degree
PhD (Doctor of Philosophy)
Psychological and Quantitative Foundations
Ehly, Stewart W.
First Committee Member
Gerken, Kathryn C.
Second Committee Member
Barron, Sheila I.
Third Committee Member
Williams, Rachel M.
Fourth Committee Member
Assouline, Susan Lynn G.
The purpose of this study was to determine the validity of the Iowa Sex Offender Risk Assessment (ISORA) instrument used in the Iowa Department of Corrections to assess for future occurrences of female offender recidivism. Using a sample of 105 females convicted of a sexual offense in the State of Iowa, the current study examined rates of recidivism using the ISORA. The goal of this study was to determine the validity of the ISORA in predicting recidivism rates as measured by (a) new convictions for sex offenses and other violent crimes, (b) new convictions for sex crimes using a strict definition, and (c) any new conviction for any new crime. Data were collected on all female participants in this study using case file information from various database resources. Mean-cost rating scores and Receiver Operating Characteristic Curve analyses were conducted to explore the relationships between risk assessment categories on the ISORA and each type of recidivism as well as between raw ISORA scores and each type of recidivism. Results showed the overall recidivism rate of female offenders was 22% for this study, while the sexual recidivism rate in this study was 2%. Results also provided evidence that the ISORA can be used to predict sexual and violent recidivism (AUC = .85) as well as general recidivism (AUC = .64) for female sex offenders. In conclusion, the ISORA is a valid risk assessment tool when predicting general and sexual or violent recidivism for female sexual offenders. However, further research examining improvements in the instrument could be conducted to enhance the validity of the instrument.
Although research is slowly coming into view regarding female sex offenders, we know very little about why women commit such crimes or how to assess and treat their behavior. Risk assessment of this population is far behind that of male sex offenders representing an obvious need to study females so that we might be able to understand and treat them just as we have done with males. Despite the fact that the number of women sex offenders is small, knowledge of this population is needed to improve the lives of these offenders and to protect the well-being of others through establishment of the likelihood of future occurrences of sexual offenses.
The purpose of this study is to examine the validity of a female sex offender risk assessment instrument, the Iowa Sex Offender Risk Assessment (ISORA), used by the State of Iowa Department of Corrections with respect to recidivism rates of a sample of female sexual offenders. My results show that the overall recidivism rate of female offenders is 22% for this study, while the sexual recidivism rate in this study is 2%, both percentages of which are fairly consistent with previous research. Further, my results show that the ISORA is a valid instrument for use with female sex offenders when predicting general criminal and sexual and violent recidivism rates.
Overall, this research indicates the ISORA is a valid risk assessment tool when predicting certain types of recidivism for female sexual offenders. However, further research examining improvements in the instrument as well as using a larger sample size could be conducted to enhance the validity of the instrument.
publicabstract, Female Sex Offenders, Recidivism
viii, 129 pages
Includes bibliographical references (pages 112-120).
Copyright 2015 Wendy J. McGinnis
McGinnis, Wendy J.. "The validity of the Iowa Sex Offender Risk Assessment for predicting recidivism in female sexual offenders." PhD (Doctor of Philosophy) thesis, University of Iowa, 2015.