The field of sex offender treatment outcome research is characterised by much debate. Some reviewers have concluded that the accumulation of evidence derived from observational studies indicates that psychological treatments reduce recidivism (Hanson et al., 2002; Lösel & Schmucker, 2005). Others however have adopted more parsimonious appraisals, concluding that the evidence is insufficient, or that scientific designs are below what is required for the outcome data to be minimally informative (Kenworthy, Adams, Brooks-Gordon, & Fenton, 2004; Rice & Harris, 2003). Results from recent systematic reviews indicate that better quality research is required before we can conclude on whether such programmes are effective or not (Walton & Chou, 2014; Långström et al. 2013; Dennis et al. 2013). In his personal view, Dr Ho does not appear to have fully considered the current need for improved research designs in supporting the conclusion that treatment is ineffective. Ho focuses his attention on the National Offender Management Services’ (NOMS) suite of accredited Sex Offender Treatment Programmes (SOTPs). In particular, he briefly reports on the ‘Core Programme’, suggesting that there is a current lack of evidence to indicate the intervention is effective at reducing recidivism. In this response, we draw attention to the state of affairs in the literature, and in particular the problems inherent with fixed claims about effects of treatment, when these are borne out of suboptimal studies fraught with systematic bias which threatens the validity of inferences drawn.
It is perhaps first important to clarify the conclusions drawn by the authors of the systematic review and meta-analysis Ho refers to in supporting his assertion that the Core Programme is ineffectual. Incidentally, the other piece of evidence he refers to (Ho & Ross, 2012) is an editorial criticising the NOMS “fact sheet” of outcome evidence. In our view, this has already been satisfactorily rebutted by Mann, Carter & Wakeling (2012). In following, Lösel and Schmucker (2005), whilst including in their data synthesis, one observational study that investigated the effect of the Core Programme on recidivism (Friendship et al., 2003), concluded that cognitive-behavioural interventions (incidentally, a therapeutic modality central to the Core programme itself) were more effective than other psychosocial approaches. Hence, it is curious that Ho draws on this meta-analysis to support his position that treatment is ineffective. On the contrary, there is a need for cautious interpretation of Lösel and Schmucker’s findings, given that the majority of included studies (60%) were rated as methodologically weak owing to the non-equivalence of comparison and treatment groups. In a field laden with weak inference studies, literature can become matted with biased outcomes, due to decisions taken in scientific design, which either artificially inflate or decrease the chances of finding a treatment effect. With observational designs especially, non-comparable groups are observed or supposed based on actual or a prior group differences which directly impact outcomes of interest independent of treatment. Therefore, there is a need to determine the direction of overall systematic bias on the observed recidivism rates (Walton & Chou, 2014). Notwithstanding their optimistic findings, the conclusion that Lösel and Schmucker (2005) support is the need for the implementation of more randomised studies.
Randomised Controlled Trials (RCTs) have been regarded as the optimal design for treatment evaluation (Harris, Rice & Quinsey, 1998; Rice & Harris, 2003; Seto et al., 2008; although see Hollin, 2008; Marshall, 2006; Marshall & Marshall, 2007; 2008 for an alternative view). Randomised assignment should offset differences that exist between large groups as well as inadvertent bias caused by the researcher during allocation. Dennis et al. (2013) limited their inclusion criteria to RCTs and concluded that there was the need for further randomised studies, since current available evidence does not support the belief that treated individuals pose a reduced risk of recidivism. Only two of the ten randomised studies they included reported recidivism rates. Results from the most well recognised randomised study reporting final data from the Sex Offender Treatment and Evaluation Project (SOTEP, Marques et al. 1994; Marques et al. 2005), indicate that a structured relapse prevention (RP) therapy has no effect on recidivism. The extent to which the SOTEP represents current treatment practice is debatable (see Seto et al. 2008; Marshall & Marshall, 2007; 2008). Nevertheless, important learning from the SOTEP has been documented (Marques et al. 2000). Certainly, dynamic risk factors (Hanson & Morton-Bourgon, 2004; 2005) which are now popularised treatment targets in modern interventions were either absent or deficient. In addition, the RP model has been criticised (Laws Hudson & Ward, 2000; Yates, 2007), and among international treatment programmes (see McGrath et al. 2010) is becoming gradually replaced by future-orientated approaches (Ward, Mann & Gannon, 2007) and the self-regulation (SR) model of relapse (Ward & Hudson, 2000). The second RCT showed that a group psychodynamic intervention had no effect on recidivism (Romero, 1983). This therapeutic modality has been replaced by cognitive-behavioural approaches, and is not representative of current practice (McGrath et al. 2010). In light of these unfavourable results, no randomised trials of primary adult sex offender treatments have been completed in what is fast approaching two decades. The bearing that results from dated interventions have on the efficacy of current treatments is debatable. Reliance on weak scientific designs, often poorly implemented, has it seems delayed the gathering of generally agreed upon knowledge. Therefore, incautious assertions about treatment effects or lack thereof, are premature until either more randomised designs are carried out or the standards of observational studies are improved such that bias is significantly reduced.
Friendship et al. (2003) have reported results that indicate the Core Programme is effective for medium risk offenders. No effects were found for higher risk offenders; a group which according to the risk principle (Bonta & Andrews, 2007) would require a higher dose of treatment than the Core Programme alone. However, these data were drawn from an observational study which has either been rated as methodologically weak (Lösel & Schmucker, 2005; Hanson et al. 2009), or excluded from systematic reviews on basis of its suboptimal design status. Therefore, bias is likely to have impacted results. NOMS cognitive-behavioural interventions for sexual offenders are centralised around Risk, Need and Responsivity principles. The clinical landscape of commissionable SOTP provision is now entering into a period of considerable change reflecting up to date intervention targets, and a need to effectively prioritise finite resources for offenders who are most likely to benefit. Use of strong inference designs to evaluate recidivism rates for offenders treated on these developing programmes would provide clearer indication as to their impact on recidivism than could be established for their predecessor.
Despite the inconsistent findings in the field, even for those preferring to rely on the most rigorous of randomised scientific trials, of which very few exist, one should be cautious as not to hastily conflate absence of evidence, with evidence of absence. Doing so increases risk of Type II error. Given that for various political and logistical reasons, observational designs will likely continue to be used in place of randomised trials, we have outlined ways forward for improvement in their implementation, so that internal validity is enhanced and greater confidence can be gained from outcome results (Walton & Chou, 2014). In our view it is also important that systematic reviewers and programme evaluators make an effort to assess the direction of bias on observed outcomes an essential part of their analytical procedure. Where directions of bias significantly diverge between individual sets of data, statistical aggregation of such data is at increased risk of being misleading. Therefore, at the very least, this process reduces chances of such misinformed analyses, and at best may have the potential to inform patterns between observed outcomes and decisions taken in scientific design. We believe that Ho’s conclusion is premature. Claiming that treatment is ineffective in the absence of consistent high quality evidence to support such a claim does not accurately convey the state of affairs in the field. Only through increasing the rigor of studies in the field together with efforts to identify the influence of residual bias on outcomes of interest can progress occur.
Sincerely
Dr Jamie Walton
Registered Practitioner Psychologist (Forensic) and Chartered Psychologist
HM Prison Service
North West Area Psychological Services
Dr Shihning Chou
Assistant Professor of Forensic Psychology,
Centre for Forensic and Family Psychology,
Division of Psychiatry & Applied Psychology, School of Medicine, University of Nottingham
Floor B, Yang Fujia Building, Jubilee Campus, Wollaton Road, Nottingham, NG8 1BB, UK
Jamie Walton is employed in HM Prison Service and is a current Treatment Manager of the Core Sex Offender Treatment Programme (SOTP) within a regional Treatment Management team. The commentary submitted represents his own views together with those of Shihning Chou and not intended to directly represent the views of HM Prison Service or the National Offender Manager Service.
References:
Bonta, J., & Andrews, D. A. (2007). Risk-need-responsivity model for offender assessment and rehabilitation (Corrections Research User Report No. 2007-06). Ottawa, ON: Public Safety Canada.
Dennis, J. A., Khan, O., Ferriter, M., Huband, N., Powney, M. J., & Duggan, C. (2012). Psychological interventions for adults who have sexually offended or are at risk of offending. (CD007507; Cochrane Database of Systematic Reviews Issue 12). Chichester, UK: John Wiley & Sons.
Friendship, C., Mann, R. E., & Beech, A. R. (2003). Evaluation of a national prison-based treatment program for sexual offenders in England and Wales. Journal of Interpersonal Violence, 18, 744–759.
Hanson, R. K., Bourgon, G., Helmus, L., & Shannon, H. (2009). The principles of effective correctional treatment also apply to sexual offenders: A meta-analysis. Journal of Criminal Justice and Behaviour, 36, 865–891.
Hanson, R. K., Gordon, A., Harris, A. J. R., Marques, J. K., Murphy, W., Quinsey, V. L., & Seto, M. C. (2002). First report of the collaborative outcome data project on the treatment of convicted adult male sex offenders. Sexual Abuse: Journal of Research & Treatment, 14, 169–194.
Hanson, R. K., & Morton-Bourgon, K. E. (2004). Predictors of sexual recidivism: An updated meta-analysis (Corrections User Report No. 2004-02). Ottawa, Ontario, Canada: Public Safety Canada.
Hanson, R. K., & Morton-Bourgon, K.E. (2005). Predicting relapse: A meta-analysis of sexual offender recidivism studies. Journal of Consulting and Clinical Psychology, 66, 348–362.
Harris, G.T., Rice, M. E., & Quinsey, V. L. (1998). Appraisal and management of risk in sexual aggression; implications for criminal justice policy. Psychology, Public Policy, and Law, 4, 73–115.
Ho D. K. & Ross C. C (2012) Cognitive behaviour therapy for sex offenders: too good to be true? Criminal Behaviour Mental Health, 22, 1-6.
Hollin, C.R. (2008). Evaluating offending behavior programs: Does only randomization glister? Criminology and Criminal Justice, 8, 89-106.
Kenworthy, T., Adams, C. E., Brooks-Gordon, B., & Fenton, M. (2004). Psychological interventions for those who have sexually offended or are at risk of offending (CD004858; Cochrane Database of Systematic Reviews, Issue 3). Chichester, England: John Wiley.
Långström, N., Enebrink, P., Laurèn, E., Lindblom, J., Werkö, S. & Hanson, K. R (2013). Preventing sex abusers of children from reoffending: systematic review of medical and psychological interventions. British Medical Journal, 347, 1 – 11.
Laws, D. R., Hudson, S. M., & Ward T. (Eds.). (2000) Remaking relapse prevention with sex offenders: A sourcebook. Newbury Park, CA: Sage.
Lösel, F., & Schmucker, M. (2005). The effectiveness of treatment for sexual offenders: A comprehensive meta-analysis. Journal of Experimental Criminology, 1, 117–146.
Mann, R. E., Carter, A. J. & Wakeling. H. C (2012) In defense of NOMS’ view about sex offending treatment effectiveness: A reply to Ho and Ross. Criminal Behaviour Mental Health, 2, 7-10.
Marshall, W. L. (2006). Appraising treatment outcome with sexual offenders. In W. L. Marshall, Y. M. Fernandez, L. E. Marshall, & G. A. Serran (Eds.), Sexual Offender Treatment: Controversial Issues (pp. 17–32). New York, NY: Wiley.
Marshall, W. L., & Marshall, L. E. (2007). The utility of randomised control trials for evaluating sexual offender treatment: The gold standard or inappropriate strategy? Journal of Sexual Abuse, 19,
175–191.
Marshall, W. L., & Marshall, L. E. (2008). Good clinical practice and the evaluation of treatment: A response to Seto et al. Sexual Abuse: A Journal of Research and Treatment, 20, 256–260.
Marques, J. K., Day, D. M, Nelson, C., & West, M. A. (1994). Effects of cognitive-behavioral treatment on sex offender recidivism: Preliminary results of a longitudinal study. Special Issue: The assessment and treatment of sex offenders. Criminal Justice and Behavior, 21, 28–54.
Marques, J. K., Wiederanders, M., Day, D. M., Nelson, C., & Van Ommeren, A. (2005). Effects of a relapse prevention program on sexual recidivism: final results from California’s sex offender treatment and evaluation project (SOTEP). Sexual abuse: A Journal of Research and Treatment, 17, 79–107.
McGrath, R., Cumming, G., Burchard, B., Zeoli, S., & Ellerby, L. (2010) Current Practices and Emerging Trends in Sexual Abuser Management: The Safer Society 2009 North American Survey. Brandon, Vermont: Safer Society Press.
Rice, M. E., & Harris, G. T. (2003). The size and sign of treatment effects in sex offender therapy. Annals of the New York Academy of Sciences, 989, 428–440.
Romero JJ, Williams LM (1983) Group psychotherapy and intensive probation supervision with sex offenders. Federal Probation 47: 36–42.
Seto, M. C., Marques, J. K., Harris, G. T., Chaffin, M., Lalumie`re, M. L., Miner, M. H., . . . Quinsey, V. L. (2008). Good science and progress in sex offender treatment are intertwined: A response to Marshall and Marshall (2007). Sexual Abuse: A Journal of Research and Treatment, 20, 247–255.
Walton, J. S. & Chou, S. (2014) The Effectiveness of Psychological Treatment for Reducing Recidivism in Child Molesters: A Systematic Review of Randomized and Nonrandomized Studies. Trauma, Violence & Abuse, 1 – 17.
Ward, T., & Hudson, S. M. (2000). A self-regulation model of relapse prevention. In D. R. Laws & S. M. Hudson & T. Ward (Eds.), Remaking Relapse Prevention with sex offenders: A sourcebook (pp. 79-101). Newbury Park: CA: Sage.
Ward, T., Mann, R. E., & Gannon, T. A. (2007). The Good Lives Model of offender rehabilitation: Clinical implications. Aggression and Violent Behavior, 12(1), 87-107.
Yates, P.M. (2007). Taking the leap: Abandoning relapse prevention and applying the self-regulation model to the treatment of sexual offenders. In D. Prescott (Ed.). Knowledge and practice: Challenges in the treatment and supervision of sexual abusers (pp. 143-174). Oklahoma City, OK: Wood ‘N’ Barnes.
Competing interests:
No competing interests
13 April 2015
Jamie. S. Walton
Registered Practitioner Psychologist (Forensic) and Chartered Psychologist
Shihning Chou (Assistant Professor of Forensic Psychology, University of Nottingham)
HM Prison Service, North West Area Psychological Services
Rapid Response:
Sex Offender Treatment: Commentary on Ho
The field of sex offender treatment outcome research is characterised by much debate. Some reviewers have concluded that the accumulation of evidence derived from observational studies indicates that psychological treatments reduce recidivism (Hanson et al., 2002; Lösel & Schmucker, 2005). Others however have adopted more parsimonious appraisals, concluding that the evidence is insufficient, or that scientific designs are below what is required for the outcome data to be minimally informative (Kenworthy, Adams, Brooks-Gordon, & Fenton, 2004; Rice & Harris, 2003). Results from recent systematic reviews indicate that better quality research is required before we can conclude on whether such programmes are effective or not (Walton & Chou, 2014; Långström et al. 2013; Dennis et al. 2013). In his personal view, Dr Ho does not appear to have fully considered the current need for improved research designs in supporting the conclusion that treatment is ineffective. Ho focuses his attention on the National Offender Management Services’ (NOMS) suite of accredited Sex Offender Treatment Programmes (SOTPs). In particular, he briefly reports on the ‘Core Programme’, suggesting that there is a current lack of evidence to indicate the intervention is effective at reducing recidivism. In this response, we draw attention to the state of affairs in the literature, and in particular the problems inherent with fixed claims about effects of treatment, when these are borne out of suboptimal studies fraught with systematic bias which threatens the validity of inferences drawn.
It is perhaps first important to clarify the conclusions drawn by the authors of the systematic review and meta-analysis Ho refers to in supporting his assertion that the Core Programme is ineffectual. Incidentally, the other piece of evidence he refers to (Ho & Ross, 2012) is an editorial criticising the NOMS “fact sheet” of outcome evidence. In our view, this has already been satisfactorily rebutted by Mann, Carter & Wakeling (2012). In following, Lösel and Schmucker (2005), whilst including in their data synthesis, one observational study that investigated the effect of the Core Programme on recidivism (Friendship et al., 2003), concluded that cognitive-behavioural interventions (incidentally, a therapeutic modality central to the Core programme itself) were more effective than other psychosocial approaches. Hence, it is curious that Ho draws on this meta-analysis to support his position that treatment is ineffective. On the contrary, there is a need for cautious interpretation of Lösel and Schmucker’s findings, given that the majority of included studies (60%) were rated as methodologically weak owing to the non-equivalence of comparison and treatment groups. In a field laden with weak inference studies, literature can become matted with biased outcomes, due to decisions taken in scientific design, which either artificially inflate or decrease the chances of finding a treatment effect. With observational designs especially, non-comparable groups are observed or supposed based on actual or a prior group differences which directly impact outcomes of interest independent of treatment. Therefore, there is a need to determine the direction of overall systematic bias on the observed recidivism rates (Walton & Chou, 2014). Notwithstanding their optimistic findings, the conclusion that Lösel and Schmucker (2005) support is the need for the implementation of more randomised studies.
Randomised Controlled Trials (RCTs) have been regarded as the optimal design for treatment evaluation (Harris, Rice & Quinsey, 1998; Rice & Harris, 2003; Seto et al., 2008; although see Hollin, 2008; Marshall, 2006; Marshall & Marshall, 2007; 2008 for an alternative view). Randomised assignment should offset differences that exist between large groups as well as inadvertent bias caused by the researcher during allocation. Dennis et al. (2013) limited their inclusion criteria to RCTs and concluded that there was the need for further randomised studies, since current available evidence does not support the belief that treated individuals pose a reduced risk of recidivism. Only two of the ten randomised studies they included reported recidivism rates. Results from the most well recognised randomised study reporting final data from the Sex Offender Treatment and Evaluation Project (SOTEP, Marques et al. 1994; Marques et al. 2005), indicate that a structured relapse prevention (RP) therapy has no effect on recidivism. The extent to which the SOTEP represents current treatment practice is debatable (see Seto et al. 2008; Marshall & Marshall, 2007; 2008). Nevertheless, important learning from the SOTEP has been documented (Marques et al. 2000). Certainly, dynamic risk factors (Hanson & Morton-Bourgon, 2004; 2005) which are now popularised treatment targets in modern interventions were either absent or deficient. In addition, the RP model has been criticised (Laws Hudson & Ward, 2000; Yates, 2007), and among international treatment programmes (see McGrath et al. 2010) is becoming gradually replaced by future-orientated approaches (Ward, Mann & Gannon, 2007) and the self-regulation (SR) model of relapse (Ward & Hudson, 2000). The second RCT showed that a group psychodynamic intervention had no effect on recidivism (Romero, 1983). This therapeutic modality has been replaced by cognitive-behavioural approaches, and is not representative of current practice (McGrath et al. 2010). In light of these unfavourable results, no randomised trials of primary adult sex offender treatments have been completed in what is fast approaching two decades. The bearing that results from dated interventions have on the efficacy of current treatments is debatable. Reliance on weak scientific designs, often poorly implemented, has it seems delayed the gathering of generally agreed upon knowledge. Therefore, incautious assertions about treatment effects or lack thereof, are premature until either more randomised designs are carried out or the standards of observational studies are improved such that bias is significantly reduced.
Friendship et al. (2003) have reported results that indicate the Core Programme is effective for medium risk offenders. No effects were found for higher risk offenders; a group which according to the risk principle (Bonta & Andrews, 2007) would require a higher dose of treatment than the Core Programme alone. However, these data were drawn from an observational study which has either been rated as methodologically weak (Lösel & Schmucker, 2005; Hanson et al. 2009), or excluded from systematic reviews on basis of its suboptimal design status. Therefore, bias is likely to have impacted results. NOMS cognitive-behavioural interventions for sexual offenders are centralised around Risk, Need and Responsivity principles. The clinical landscape of commissionable SOTP provision is now entering into a period of considerable change reflecting up to date intervention targets, and a need to effectively prioritise finite resources for offenders who are most likely to benefit. Use of strong inference designs to evaluate recidivism rates for offenders treated on these developing programmes would provide clearer indication as to their impact on recidivism than could be established for their predecessor.
Despite the inconsistent findings in the field, even for those preferring to rely on the most rigorous of randomised scientific trials, of which very few exist, one should be cautious as not to hastily conflate absence of evidence, with evidence of absence. Doing so increases risk of Type II error. Given that for various political and logistical reasons, observational designs will likely continue to be used in place of randomised trials, we have outlined ways forward for improvement in their implementation, so that internal validity is enhanced and greater confidence can be gained from outcome results (Walton & Chou, 2014). In our view it is also important that systematic reviewers and programme evaluators make an effort to assess the direction of bias on observed outcomes an essential part of their analytical procedure. Where directions of bias significantly diverge between individual sets of data, statistical aggregation of such data is at increased risk of being misleading. Therefore, at the very least, this process reduces chances of such misinformed analyses, and at best may have the potential to inform patterns between observed outcomes and decisions taken in scientific design. We believe that Ho’s conclusion is premature. Claiming that treatment is ineffective in the absence of consistent high quality evidence to support such a claim does not accurately convey the state of affairs in the field. Only through increasing the rigor of studies in the field together with efforts to identify the influence of residual bias on outcomes of interest can progress occur.
Sincerely
Dr Jamie Walton
Registered Practitioner Psychologist (Forensic) and Chartered Psychologist
HM Prison Service
North West Area Psychological Services
Dr Shihning Chou
Assistant Professor of Forensic Psychology,
Centre for Forensic and Family Psychology,
Division of Psychiatry & Applied Psychology, School of Medicine, University of Nottingham
Floor B, Yang Fujia Building, Jubilee Campus, Wollaton Road, Nottingham, NG8 1BB, UK
Jamie Walton is employed in HM Prison Service and is a current Treatment Manager of the Core Sex Offender Treatment Programme (SOTP) within a regional Treatment Management team. The commentary submitted represents his own views together with those of Shihning Chou and not intended to directly represent the views of HM Prison Service or the National Offender Manager Service.
References:
Bonta, J., & Andrews, D. A. (2007). Risk-need-responsivity model for offender assessment and rehabilitation (Corrections Research User Report No. 2007-06). Ottawa, ON: Public Safety Canada.
Dennis, J. A., Khan, O., Ferriter, M., Huband, N., Powney, M. J., & Duggan, C. (2012). Psychological interventions for adults who have sexually offended or are at risk of offending. (CD007507; Cochrane Database of Systematic Reviews Issue 12). Chichester, UK: John Wiley & Sons.
Friendship, C., Mann, R. E., & Beech, A. R. (2003). Evaluation of a national prison-based treatment program for sexual offenders in England and Wales. Journal of Interpersonal Violence, 18, 744–759.
Hanson, R. K., Bourgon, G., Helmus, L., & Shannon, H. (2009). The principles of effective correctional treatment also apply to sexual offenders: A meta-analysis. Journal of Criminal Justice and Behaviour, 36, 865–891.
Hanson, R. K., Gordon, A., Harris, A. J. R., Marques, J. K., Murphy, W., Quinsey, V. L., & Seto, M. C. (2002). First report of the collaborative outcome data project on the treatment of convicted adult male sex offenders. Sexual Abuse: Journal of Research & Treatment, 14, 169–194.
Hanson, R. K., & Morton-Bourgon, K. E. (2004). Predictors of sexual recidivism: An updated meta-analysis (Corrections User Report No. 2004-02). Ottawa, Ontario, Canada: Public Safety Canada.
Hanson, R. K., & Morton-Bourgon, K.E. (2005). Predicting relapse: A meta-analysis of sexual offender recidivism studies. Journal of Consulting and Clinical Psychology, 66, 348–362.
Harris, G.T., Rice, M. E., & Quinsey, V. L. (1998). Appraisal and management of risk in sexual aggression; implications for criminal justice policy. Psychology, Public Policy, and Law, 4, 73–115.
Ho D. K. & Ross C. C (2012) Cognitive behaviour therapy for sex offenders: too good to be true? Criminal Behaviour Mental Health, 22, 1-6.
Hollin, C.R. (2008). Evaluating offending behavior programs: Does only randomization glister? Criminology and Criminal Justice, 8, 89-106.
Kenworthy, T., Adams, C. E., Brooks-Gordon, B., & Fenton, M. (2004). Psychological interventions for those who have sexually offended or are at risk of offending (CD004858; Cochrane Database of Systematic Reviews, Issue 3). Chichester, England: John Wiley.
Långström, N., Enebrink, P., Laurèn, E., Lindblom, J., Werkö, S. & Hanson, K. R (2013). Preventing sex abusers of children from reoffending: systematic review of medical and psychological interventions. British Medical Journal, 347, 1 – 11.
Laws, D. R., Hudson, S. M., & Ward T. (Eds.). (2000) Remaking relapse prevention with sex offenders: A sourcebook. Newbury Park, CA: Sage.
Lösel, F., & Schmucker, M. (2005). The effectiveness of treatment for sexual offenders: A comprehensive meta-analysis. Journal of Experimental Criminology, 1, 117–146.
Mann, R. E., Carter, A. J. & Wakeling. H. C (2012) In defense of NOMS’ view about sex offending treatment effectiveness: A reply to Ho and Ross. Criminal Behaviour Mental Health, 2, 7-10.
Marshall, W. L. (2006). Appraising treatment outcome with sexual offenders. In W. L. Marshall, Y. M. Fernandez, L. E. Marshall, & G. A. Serran (Eds.), Sexual Offender Treatment: Controversial Issues (pp. 17–32). New York, NY: Wiley.
Marshall, W. L., & Marshall, L. E. (2007). The utility of randomised control trials for evaluating sexual offender treatment: The gold standard or inappropriate strategy? Journal of Sexual Abuse, 19,
175–191.
Marshall, W. L., & Marshall, L. E. (2008). Good clinical practice and the evaluation of treatment: A response to Seto et al. Sexual Abuse: A Journal of Research and Treatment, 20, 256–260.
Marques, J. K., Day, D. M, Nelson, C., & West, M. A. (1994). Effects of cognitive-behavioral treatment on sex offender recidivism: Preliminary results of a longitudinal study. Special Issue: The assessment and treatment of sex offenders. Criminal Justice and Behavior, 21, 28–54.
Marques, J. K., Wiederanders, M., Day, D. M., Nelson, C., & Van Ommeren, A. (2005). Effects of a relapse prevention program on sexual recidivism: final results from California’s sex offender treatment and evaluation project (SOTEP). Sexual abuse: A Journal of Research and Treatment, 17, 79–107.
McGrath, R., Cumming, G., Burchard, B., Zeoli, S., & Ellerby, L. (2010) Current Practices and Emerging Trends in Sexual Abuser Management: The Safer Society 2009 North American Survey. Brandon, Vermont: Safer Society Press.
Rice, M. E., & Harris, G. T. (2003). The size and sign of treatment effects in sex offender therapy. Annals of the New York Academy of Sciences, 989, 428–440.
Romero JJ, Williams LM (1983) Group psychotherapy and intensive probation supervision with sex offenders. Federal Probation 47: 36–42.
Seto, M. C., Marques, J. K., Harris, G. T., Chaffin, M., Lalumie`re, M. L., Miner, M. H., . . . Quinsey, V. L. (2008). Good science and progress in sex offender treatment are intertwined: A response to Marshall and Marshall (2007). Sexual Abuse: A Journal of Research and Treatment, 20, 247–255.
Walton, J. S. & Chou, S. (2014) The Effectiveness of Psychological Treatment for Reducing Recidivism in Child Molesters: A Systematic Review of Randomized and Nonrandomized Studies. Trauma, Violence & Abuse, 1 – 17.
Ward, T., & Hudson, S. M. (2000). A self-regulation model of relapse prevention. In D. R. Laws & S. M. Hudson & T. Ward (Eds.), Remaking Relapse Prevention with sex offenders: A sourcebook (pp. 79-101). Newbury Park: CA: Sage.
Ward, T., Mann, R. E., & Gannon, T. A. (2007). The Good Lives Model of offender rehabilitation: Clinical implications. Aggression and Violent Behavior, 12(1), 87-107.
Yates, P.M. (2007). Taking the leap: Abandoning relapse prevention and applying the self-regulation model to the treatment of sexual offenders. In D. Prescott (Ed.). Knowledge and practice: Challenges in the treatment and supervision of sexual abusers (pp. 143-174). Oklahoma City, OK: Wood ‘N’ Barnes.
Competing interests: No competing interests