Validation of the PPG

The Penile Plethysmograph Meets and Exceeds the Daubert Standard

  1. Whether the theory used by the expert can be and has been tested. 
  2. Whether the theory or technique has been subjected to peer review.
  3. The known or potential rate of error of the method used.
  4. The degree of the methods or conclusion’s acceptance within the relevant scientific community.
  1. Daubert – Whether the theory used by the expert can be and has been tested.
    • A)  The theory used is based on the human sexual response cycle as outline by Masters & Johnson.
      • Stage I: Excitement Phase (for males includes degrees of penile erection)
      • Stage II: Plateau Phase (for males includes Corona / Corpus spongiosum of further engorgement of the penis)
      • Stage III: Orgasmic Phase
      • Stage IV: Resolution Phase
      • (Masters,  W. H. & Johnson, V.E. [1966]. Human Sexual Response. Lippincott Williams & Wilkins)
    • B) Singer’s Three Stage Model of Sexual Arousal: 
      • Stage I:  Aesthetic Response–an emotional reaction to noticing an attractive face or figure
      • Stage I:  Aesthetic Response–an emotional reaction to noticing an attractive face or figure
      • Stage III:  Genital Response—In this stage, one recognizes that with both attention and closer proximity, physical reactions result in genital tumescence. Singer also notes that there is an array of other autonomic responses, but acknowledges that the research literature suggests that the genital response is ‘‘the most reliable and convenient to measure’’ in males
      • (Singer, B. Conceptualizing sexual arousal and attraction. The Journal of Sex Research. 1984; 20, 230–240)

2. Daubert – Has the technique been subject to peer review and publication? 

The PPG has been extensively tested over decades of peer-reviewed research.  Please see the Literature Review at the end of this section.  

3. Daubert – The known or potential rate of error of the method used.

Standardization

Both Monarch Systems and Limestone Systems have research-based standardized protocols and certification programs that ensure standardization of testing conditions, test instructions, scoring and interpretation methodology, as well as report writing.  

Error Rate, Validity, and Specificity

In terms of a “hit rate”, Card and Dibble (1995), correctly classified 46 out of 52 subjects, which was 88%. With a completely different sample Byrne (2000) correctly classified 82 out of 95 subjects for an 86% hit rate. The true positive rate (sensitivity) was found to be .89 and specificity, the true negative rate was .85. The ability of the assessment stimuli to predict correctly the presence of pedophilia (positive predictive power or PPP) was .78. Their ability to predict the absence of pedophilia (negative predictive power or NPP) was .93. The PPG has a known error rate with a very high NPP for predicting the absence of pedophilia. 

How consistently does a test reproduce results?

Coefficient alpha varies from 0.0 to 1.0, with alphas below .70 considered low (Nunnally, 1978). Letourneau found .85 Cronbach’s Alpha scores on PPG focusing on arousal to children (page 215).

  • Sensitivity is the percentage of correctly identifying—in this case–those men who are sexually aroused to specific stimuli (i.e., child stimulus = arousal to children or rape stimulus= arousal to rape scenarios). 
  • Specificity is the percentage of correctly identified men who are not aroused to deviant stimuli (i.e., children, rape, etc.). 
  • Sensitivity & Specificity relate to single category results (i.e., male children).

The Monarch System 2003 training manual by David Byrn reports a Sensitivity rate of .71 and a Specificity rate of .94.

The Limestone training manual (current) shows a Sensitivity rate of .74 and a Specificity rate of .95.  This was based on research by William Burke and Gregg Dwyer and presented at the 2006 ATSA International Conference.  

Discriminate Validity

Penile responses can distinguish heterosexual and homosexual men, men who are sexually attracted to prepubescent children from those who are sexually attracted to adults, fetishists from nonfetishists, rapists from nonrapists, and sadistic men from nonsadistic men (e.g., Blanchard, Klassen, Dickey, Kuban & Blak, 2001; Freund, 1963; Freund, Seto, & Kuban, 1996; Lalumière, Quinsey, Harris, Rice, & Trautrimas, 2003; Sakheim et al., 1985; Seto & Kuban, 1996). Penile responses can also distinguish sexually functional men from men with sexual dysfunctions, such as men with premature ejaculation (Rowland, van Diest, Incrocci, & Slob, 2005).

Predictive Validity

Phallometrically-assessed sexual arousal to stimuli depicting children or sexual violence is an important predictor of sexual reoffending among sex offenders (Hanson & Morton-Bourgon, 2005). Although the predictive validity of phallometrically-assessed sexual arousal in nonforensic samples has not been systematically examined, one study found that penile responses to sexual stimuli in the laboratory were related to increases in sexual behavior on the day following the laboratory session (Both, Spiering, Everaerd, & Laan, 2004).

Countermeasures against faking & voluntary control by test subjects.

Dissimulation in Phallometric Testing of Rapists’ Sexual Preferences. 

Harris G.T.; Rice M.E.; Chaplin T.C.;Quinsey V.L. (1999). Archives of Sexual Behavior, Volume 28, Number 3, 1 June 1999 , pp. 223-232(10)

Preventing faking in phallometric assessments of sexual preference.  

Quinsey & Chapman (1988). Annals of the New York Academy of Sciences, Vol 528, Issue 1 49-58, Copyright © 1988 by New York Academy of Sciences . 

The experiment was to test the efficacy of a tracking task during a ppg study in which the participants were instructed to attempt to fake or suppress their arousal. Groupdata indicated that subjects could fake inappropriate preferences wheninstructed to do so without the semantic tracking task but could not whenthe task was required. 

Phallometric Nonresponding in Sexual Offenders. 

Looman J.; Abracen J.; Maillet G.; DiFazio R. (1988). 

Sexual Abuse: A Journal of Research and Treatment, Volume 10, Number 4, pp. 325-336(12).

4. Daubert – The degree of the methods or conclusion’s acceptance within the relevant scientific community.

a) The American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders (DSM-5) has gone from not recommending physiological assessments in DSM-IV to specifically identifying it use in DSM-5. “Psychophysiological measures of sexual interest may sometimes be useful . . . The most thoroughly researched and longest used of such measures is penile plethysmography, . . . Viewing time, . . . is also used to diagnose pedophilic disorder, especially in combination with self-report measures.”                                                 (DSM-5, pp.698-699)

b) The Association for the Treatment of Sexual Abusers publishes a Standards of Care document. Phallometry is considered a necessary component of an evaluation that meets the standards of care established by ATSA.  PPG is referenced as a part of an evaluation that meets the Standards of Care on page 16 and in Appendix A.

c) The FDA considers the PPG to be a Class II medical device.  The PPG is not 510(k) exempt. The 510(k) submission allows the FDA to determine whether a device is generally equivalent to a similar one already on the market.  The PPG is also not exempt from the FDA’s GMP (good manufacturing practice) regulations.

d) Hanson and Bussiere, (1998) published a comprehensive meta-analysis of 61 scientific reports on the prediction of sexual offenses spanning more than 40,000 individual cases. They ascertained that of all the methods attempted and reported, penile phethysmographic responses to imagery depicting children was the single most accurate predictor of sexual re-offense across 7 studies reporting data from phallometric testing.  “Deviant sexual arousal as measured by phallometry was found to be the single best predictor of sexual recidivism among child molesters.” 

Predicting relapse: A meta-analysis of sexual offender recidivism studies. 

Journal of Consulting and Clinical Psychology. Hanson R. K.; Bussière M. T. (1998). 66: 348–362.

e) “PPG remains the single best measurement of deviant arousal.” (page 203)

A Comparison of Objective Measures of Sexual Interests and Arousal: Visual Reaction Time and Penile Plethysmography. Sexual Abuse: A Journal of Research and Treatment. Vol 14, No. 3 (2002).

f) A meta-analysis in 2005 of 13 studies and 2,180 individual cases repeated the finding that phallometric responses to children was a strong predictor of sexual re-offense.  

The characteristics of persistent sexual offenders: A meta-analysis of recidivism studies.
Hanson R. K.; Morton-Bourgon K. E. (2005). Journal of Consulting and Clinical Psychology. 73: 1154–1163.

g) A more recent meta-analysis that included 16 samples and 2,709 sexual offenders replicated and extended the previous findings that phallometric responding to children is a predictor of sexual re-offence. This meta-analysis extended previous meta-analytic research by showing phallometric responding to both male and female pedophilic and hebephilic stimuli predict sexual re-offence. Further, this meta-analysis showed that phallometric testing predicts sexual re-offence in distinct subgroups of sexual offenders against children. 

Validity in phallometric testing for sexual interests in children: A meta-analytic review.
Ian V. McPhail, et.al., Assessment, March 2017
Abstract

Valid assessment of pedohebephilic interests (i.e., sexual interest in children) is fundamental to forensic clinical practice.  Phallometric testing – which measure changes in penile circumference or volume while stimuli depicting different ages and sexual activities are presented – is widely used in clinical and research settings to detect such interests.  This meta-analysis summaries studies comparing sexual offenders against children and various types of controls on phallometric tests for pedohebephilic interests (37 samples; N = 6,785) and studies examining the relationship between phallometric test scores and sexual re-offending (16 samples, N = 2,709).  The findings suggest that several phallometric testing procedures are valid indicators of pedohebephilic interest.  Certain methodological features of phallometric tests were associated with greater validity, such as slide or audio-plus-slide stimuli and z-score based indices.  In addition, phallometric tests for pedohebephilic, pedophilic, and hebephilic interests predicted sexual re-offending which provides further evidence that phallometric test scores are valid indicators of sexual interest in children.  In general, the interpretation of phallometric test scores as indicators of pedohebephilic interests is supported.  

h) Arizona District Court decision

Olmos v. Ryan

No. CV-11-00344-PHX-GMS

United State District Court, D. Arizona

June 24, 2013

Olmos contends that his counsel should have argued that the requirement that he submit to penile plethysmograph testing violated the Eighth Amendment’s prohibition on cruel and unusual punishment. “Penile plethysmograph testing is a procedure that `involves placing a pressure-sensitive device around a man’s penis, presenting him with an array of sexually stimulating images, and determining his level of sexual attraction by measuring minute changes in his erectile responses.’” United States v. Weber, 451 F.3d 552, 554 (9th Cir. 2006) (quoting Jason R. Odeshoo, Of Penology and Perversity: The Use of Penile Plethysmography on Convicted Child Sex Offenders, 14 Temp. Pol. & Civ. Rts. L. Rev. 1, 2 (2004)). The Ninth Circuit has upheld the use of penile plethysmograph in certain instances as a condition of supervised release. See id. Numerous other courts have also so held. See id. at 566 (collecting cases). Plethysmograph testing has been recognized by some psychologists and researchers as a useful technique in the treatment of sexual offenders. Id. at 565. In light of the substantial weight of caselaw upholding the requirement of penile plethysmograph testing as a condition of supervised release, the Court cannot say counsel’s refusal to raise an Eighth Amendment challenge to the practice fell below an objective standard of reasonableness. Olmos has failed to show cause to excuse his procedural default of Claim Ten.

i) Eighteenth Judicial Circuit, in and for Seminole County, Florida found:

“PPG evidence is admissible in this case both under Frye and Daubert.  Such evidence is neither new nor novel, so a Frye inquiry would be improper.  State v. Fulwood, 22 So.3d 655 (Fla. 3d DCA 2009). That determination is binding on this Court.  Conley v. State, 129 So. 3d 1120, 1121 (Fla. 1st DCA 2013).  Thus, under the Frye framework, PPG evidence is admissible.  

Based upon the evidence presented, the results of the PPG testing would also be admissible under Daubert.  Drs. Wilson and Deitchman both testified about the usefulness of PPG testing based upon their substantial experience with conducting the tests and their familiarity with the literature and studies regarding those tests. . . As to PPG testing, then, this Court finds that the underlying principals and methods are scientifically reliable and Dr. Deitchman conducted the test in a scientifically reliable manner as applied to the facts of this case.  As such, the expert opinion testimony on PPG testing is admissible under Daubert.  

Re: the commitment of Jeff C. Rivers-Finney

Eighteenth Judicial Circuit, in and for Seminole County, Florida.  

December 16, 2015

Research on the PPG

Measurement of sexual arousal in several paraphilias: The effects of stimulus modality, instructional set and stimulus content on the objective.

Abel, Gene G., et al. 

Behaviour Research and Therapy, Vol 19(1), 1981. pp. 25-33.

Abstract:

Determined the effects of instructional set (become aroused or suppress arousal), stimulus modality (videotape, audiotape, slides, free fantasy), and deviant or nondeviant (i.e., paraphilic or nonparaphilic) stimulus content on sexual arousal (measured by penile plethysmograph) of 6 different groups of paraphilics—pedophiles, rapists, exhibitionists, homosexuals, sado-masochists, and fetishists. Results from 48 males (ages 16–52 yrs) show significant main effects of instructional set and stimulus modality (videotape was more arousing), as well as several complex interactions of diagnostic group with the other independent variables.

Inhibiting sexual arousal to children: Correlates and its influence on the validity of penile plethysmography.

Babchishin, Kelly M., Kelly, Babchishin., Curry, Susan D., Fedoroff, J. Paul., Bradford, John., Seto, Michael C.. 

Archives of Sexual Behavior, Vol 46(3), Apr, 2017. pp. 671-684.

Abstract:

The current study examined the extent to which 1136 men were able to inhibit their sexual arousal on a phallometric assessment, when instructed to do so. Although the observed changes between the two conditions (i.e., Normal and Suppression) were small to moderate in magnitude, the change was not more than what would be expected by measurement error for most participants (e.g., 83% of pedophilic sex offenders against children did not successfully inhibit their sexual arousal in the Suppression condition). There were very few variables that were associated with the ability to suppress. Higher Pedophilia Index scores in the Suppression condition predicted a greater likelihood of sexual recidivism among sex offenders (hazard ratio = 1.17, 95% CI [1.04, 1.32]), but the ability to suppress sexual arousal was not found to predict sexual recidivism. The current study highlights the importance of accounting for measurement error and found that, when doing so, most sex offenders against children are unable to successfully inhibit their sexual arousal to children when instructed to do so, and that the ability to suppress sexual arousal is not associated with recidivism. 

Erectile responses among heterosexual child molesters, father-daughter incest offenders, and matched non-offenders: Five distinct age preference profiles

Barbaree, H. E., & Marshall, W. L. (1989). Canadian Journal of Behavioural Science, 21, 70-82. 

The differentiation of intrafamilial and extrafamilial heterosexual child molesters. 

Barsetti, I., Earls, C., Lalumière, M. L., & Bélanger, N. (1998). Journal of Interpersonal Violence, 13, 275-286. 

Deviant sexual behavior: Differentiating sex offenders by criminal and personal history, psychometric measures, and sexual response. 

Baxter, D. J., Marshall, W. L., Barbaree, H. E., Davidson, P. R., & Malcolm, P. B. (1984). Criminal Justice and Behavior, 11, 477-501. 

Sensitivity and specificity of the phallometric test for pedophilia in nonadmitting sex offenders. 

Blanchard, R., Klassen, P., Dickey, R., Kuban, M. E., & Blak, T. (2001). Psychological Assessment, 13, 118-126. 

Phallometric comparison of pedophilic interest in nonadmitting sexual offenders against stepdaughters, biological daughters, other biologically related girls, and unrelated girls. 

Blanchard, R., Kuban, M. E., Blak, T., Cantor, J. M., Klassen, P., & Dickey, R. (2006). Sexual Abuse: A Journal of Research and Treatment, 18, 1-14. 

What is “Deviant?” An Examination of Three Distinct Groups’ Penile Plethysmograph Responses. 

Byrne, P.M. & Card, R.D. A paper presented at the 18th Annual Research & Treatment Conference of the Association for the Treatment of Sexual Abusers (ATSA), Orlando, Florida, October 1999. 

The reliability and validity of less explicit audio and ‘clothed’ visual penile plethysmograph stimuli with child molesters and nonoffenders.

Byrne, Peter M. 

Dissertation Abstracts International: Section B: The Sciences and Engineering, Vol 61(12-B), Jun, 2001. pp. 6753.

Abstract:

A well-documented predictor of the sexual recidivism of child molesters is deviant responding on the penile plethysmograph (PPG). However, the routine use of explicit audio and nude child visual stimuli in PPG have created ethical and legal barriers for practitioners treating this population. It was hypothesized that an alternative set of less explicit audio and ‘clothed’ visual stimuli would be valid at discriminating between high- and low-risk child molesters and nonoffenders. It was also hypothesized that responses to the stimuli by nonoffenders would represent their self-reported sexual preference. Results showed adequate initial indications of reliability. The discriminant validity hypotheses with child molesters and nonoffenders were supported. Nonoffender results were partially supported. The results are discussed with attention to the prior PPG research with offenders and nonoffenders, the criteria used for grouping child molesters, scoring procedures, and implications for clinical assessment and practice.

Research methods, statistical analysis, and the phallometric test for hebephilia: Response to fedoroff.

Cantor, James M. Journal of Sexual Medicine, Vol 12(12), Dec, 2015. pp. 2499-2500.

Abstract:

Reply by the James M. Cantor to the comments made by P. Fedoroff (see record 2015-43698-005) on the article Sensitivity and Specificity of the Phallometric Test for Hebephilia. (see record 2015-37962-001). Fedoroff expressed skepticism regarding my team’s analysis of the sensitivity and specificity of phallometry for distinguishing hebephilic from teleiophilic men. Despite its confident tone, however, the commentary simply misunderstands how to analyze and interpret phallometric data. Fedoroff’s fundamental misunderstanding here is that sensitivity/specificity research does not— indeed cannot—be conducted with representative samples. Sensitivity/specificity research is a test of the test, not a test of the samples. Thus alerted to the correct procedure, one can readily recognize Fedoroff’s errors. Fedoroff next claimed that the results were ‘meaningless’ because it rejected the 5% of cases who did not show 1.0 cc or greater penile volume increase, a claim that is also in error. Indeed, rejection of low-responders does not pertain to validity at all; it pertains to generalizability. Finally, despite multiple readings, Fedoroff’s last point remains entirely obscure. The age group he mentioned (’14 − 17′) is incorrect: Men interested most in 14-year-olds were actually included in the hebephilic group, and men most interested in 17-year-olds, in the teleiophilic group. 

Detecting faked penile responses to erotic stimuli: A comparison of stimulus conditions and response measures.

Card, Robert D., Farrall, William

Annals of Sex Research, Vol 3(4), 1990. pp. 381-396.

Abstract:

18 male clients at a counseling and psychotherapy clinic were told to fake penile responses to discrete sexual stimuli presented auditorily or visually. The same stimuli were presented a 2nd time following instruction on faking. Sexual responses were monitored using a penileplethysmograph (PPG); measures to detect faking attempts included galvanic skin response (GSR) and respiration (RESP). Faking attempts were more successful in response to audio than visual stimuli, especially if the stimuli were relatively weaker. Arousal was much more difficult to fake than suppression. The more intense the efforts to fake, especially following instructions, the more transparent the faking efforts. GSR and RESP added measurably to the detection of faked PPG responses that otherwise would have appeared to be genuine.

Stimulus Choice in Phallometric Assessments.

Card, R.D. & Byrne, P. M. (1996). A paper presented at the 15th Annual Research and Treatment Conference of the Association for the Treatment of Sexual Abusers (ATSA), Chicago, IL, November 1996. 

Standardization, Ethics, and Faking. 

Card, R.D. & Byrne, P. M. (1997). ATSA Forum, 9, 3, pp. 3-4. 

Predictive value of the Card/Farrall stimuli in discriminating between gynephilic and pedophilic sexual offenders. 

Card, R.D., & Dibble, A. (1995). Sexual Abuse: A Journal of Research and Treatment, 7, 129-141. 

Detecting faked responses to erotic stimuli: A comparison of stimulus conditions and response measures. 

Card, R.D., & Farrall, W.R. (1990). Annals of Sex Research, 3, 381-396. 

Salient victim suffering and the sexual responses of child molesters. 

Chaplin, T. C., Rice, M. E., & Harris, G. T. (1995). 

Journal of Consulting and Clinical Psychology, 63, 249-255. 

Relationship between key variables in penile plethysmograph and viewing time measures of sexual arousal in sex offending adult males.

Cloyd, Lisa Loewinger. 

Dissertation Abstracts International: Section B: The Sciences and Engineering, Vol 68(12-B), 2008. pp. 8440.

Abstract:

Penile plethysmography is amongst the best measures for prediction of sexual recidivism and has been extensively researched. However, there are a variety of criticisms regarding use of penile plethysmography (PPG), including financial investment, significant training needs, lack of standardization, intrusive nature of the measure, extensive time for testing, and inability to use PPG with all groups of sexual offenders (e.g., women and adolescents). Viewing time has been studied, though not as extensively as PPG, regarding detection of sexual interest. This study examined the relationship between Monarch 21 PPG and Affinity viewing time variables, including responses to individual stimuli, a sex deviance differential, and a sex deviance ratio. It was predicted that there would be a significant positive correlation between key variables of the Monarch 21 PPG and Affinity. Overall, the associations found between the Monarch 21 PPG and the Affinity were significant, although the magnitudes of the associations were modest. When considering sexual deviance ratios and differentials (as is typically utilized in PPG literature), there was a small, but significant association between the Monarch 21 PPG and the Affinity. Consequently, it is recommended that more research be done comparing these two sets of measures, further evaluating the Affinity and its’ predictive validity, and examining the complex arousal pattern shapes, rather than focusing only on a series of discrete variables. 

Development of a stimulus set for assessing the arousal patterns of sex offenders using a visual format with audio stories and still photographs. 

Farrall, W.R. (1991). 

Unpublished doctoral dissertation, the Institute for Advanced Study of Human Sexuality, San Francisco. 

Advancements in physiological evaluation of assessment and treatment of the sexual aggressor. 

Farrall, W.R., & Card, R.D. (1988). 

In R.A. Prentky & V.L. Quinsey (Eds.) Human sexual aggression: Current perspectives (pp. 261-273). New York: New York Academy of Sciences. 

Regression to the mean or the Semmelweis reflex?

Fedoroff, J. Paul., et.al.

Archives of Sexual Behavior, Vol 45(7), Oct, 2016. pp. 1869-1870.

Abstract:

Comments on an article by Andreas Mokros and Elmar Habermeyer (see record 2015-53261-001). Mokros and Harbermeyer claimed that ‘regression to the mean in combination with low reliability does indeed provide an exhaustive explanation for the results [of our study].’ The authors respectfully respond that invoking two phenomena (regression to the mean and reliability) to explain an observation is not the same as refuting the alternative explanation, which is that sexual arousal patterns as measured by phallometry can change in the same way that the performance of cadets can change.

Diagnosing heterosexual pedophilia by means of a test for sexual interest. 

Freund, K. (1965). Behaviour Research and Therapy, 3, 229-234. 

Erotic preference in pedophilia

Freund, K. (1967). Behaviour Research and Therapy, 5, 339-348. 

Phallometric diagnosis of pedophilia. 

Freund, K., & Blanchard, R. (1989). Journal of Consulting and Clinical Psychology, 57, 100-105. 

Assessment of the sensitivity and specificity of a phallometric test: An update of phallometric diagnosis of pedophilia. 

Freund, K., & Watson, R. J. (1991). Psychological Assessment, 3, 254-260. 

The effects of secondary stimulus characteristics on men’s sexual arousal.

Gaither, George A., Plaud, Joseph J. Journal of Sex Research, Vol 34(3), 1997. pp. 231-236.

Abstract:

Examined the effects of 2 stimulus characteristics that may greatly influence the measurement of male sexual arousal: (1) the type of sexual behavior depicted, and (2) the presence of accompanying audio cues. The sexual arousal of 18 male college students (mean age 23.68 yrs) was individually assessed via penile plethysmograph and self-report while they viewed 60-sec erotic video clips. Each video clip depicted a single sexual behavior; half of the clips were presented with accompanying audio. Repeated ANOVAs revealed significant main effects for sound and behavior for both the physiological and self-report data, as well as a significant sound by behavior interaction for the self-report data. The physiological data and self-report data were also highly correlated. Results are discussed in the context of implications for male sexual arousal research and penile plethysmographic assessments. 

Dissimulation in Phallometric Testing of Rapists’ Sexual Preferences. 

Harris G.T.; Rice M.E.; Chaplin T.C.;Quinsey V.L. (1999). Archives of Sexual Behavior, Volume 28, Number 3, 1 June 1999 , pp. 223-232(10)

Aggression and erotic attraction toward children in incestuous and pedophilic men. 

Lang, R. A., Black, E. L., Frenzel, R. R., & Checkley, K. L. (1988). 

Annals of Sex Research, 1, 417-441.

A survey of plethysmographic assessment in North America.

Howes, Richard J.

Sexual Abuse: Journal of Research and Treatment, Vol 7(1), Jan, 1995. pp. 9-24.

Abstract:

Surveyed North American plethysmographic assessment centers to examine the extent to which variability exists among them. 48 of 153 plethysmograph assessment centers in North America responded to a mail questionnaire. Data show that 75% of men tested at these centers were incarcerated sex offenders and sex offenders on parole or probation. Results reveal a field in which there is abundant inconsistency in both plethysmographic assessment procedures and data interpretation. A critical need for standardization was identified if plethysmographic assessment is to develop its potential in the assessment and treatment of sex offenders. The validity of penile measurement in light of predictive uses is discussed, and the issue of whether volumetric or circumferential measurement is superior is addressed.

The sensitivity and specificity of phallometric assessment and the Abel assessment for sexual interest among a group of sexual offenders against children and other sexual offenders.

Lanham, Debra

Dissertation Abstracts International: Section B: The Sciences and Engineering, Vol 73(7-B) (E), 2013.

Abstract:

This study sought to examine the validity of the Penile Plethysmograph and the Abel Assessment for Sexual Interest. Specifically, the PPG and the AASI were examined in terms of their ability to distinguish sexual offenders against children from other offenders and to see if the newer screening instrument, the AASI, was able to perform as well as the PPG at distinguishing between the two groups. Results of this study revealed limited evidence that either the PPG or the AASI could distinguish between the two groups in terms of concurrent validity, although results indicate that the PPG was approaching significance (p = .09). Both the PPG and the AASI had good sensitivity (96.7%, 91.7% respectively); however, specificity was low (10.5%, 24.3%, respectively). A secondary analysis examined atypical sexual interest variables that are associated with increased risk for re-offense, such as having multiple child victims, having any male victims, and having any extrafamilial victims to determine if these variables were associated with greater deviance on the PPG and the AASI. This hypothesis was not supported with the PPG. Having any male victims and having extrafamilial victims were both associated with greater AASI viewing time scores in the Young Female (ages 4–6) category only. A final analysis examined the convergent validity of the two measures and found that the PPG 8–10 year old stimulus category was moderately correlated with the AASI 8–10 year-old stimulus category (r = .34 for young females, r = .40 for young males). Neither the 4–10 year-old stimulus categories nor the adult categories were significantly correlated.

Classification of child molesters by plethysmographic assessment of sexual arousal and a self-report measure of sexual preference.

Laws, D. R., et al. 

Journal of Interpersonal Violence, Vol 15(12), Dec, 2000. pp. 1297-1312.

Abstract:

The present study examined the extent to which the use of multiple measures of pedophilic interest improved on the diagnostic accuracy of any single measure. Seventy-two child molesters completed a self-report card-sort measure of sexual interest, as well as direct monitoring of penileresponse (penile plethysmograph-PPG) when presented with erotic slides or audio material. The reliability of all measures was high. All three measures of pedophilic interest (i.e., card sort, PPG slides, PPG audio) significantly differentiated boy-object and girl-object child molesters. The card-sort measure showed the greatest classification accuracy and was the only measure to significantly improve accuracy, once the other two modalities were considered. Consideration of all three modalities provided classification accuracy greater than any single measure. 

Plethysmography: Will we ever get it right? 

Laws, D.R. (2003). In T. Ward, D.R. Laws, & S.M. Hudson (Eds) 

Sexual Deviance: Issues & Controversies (pp. 82- 102). 

Penile Plethysmography: Strengths, Limitations, Innovations

Laws, D.R. (2009). In Thornton, D. and Laws, D.R. (eds) Cognitive Approaches to the Assessment of Sexual Interest in Sexual Offenders (pp. 7-29). 

A Comparison of Objective Measures of Sexual Arousal and Interest: Visual Reaction Time and Penile Plethysmography.

Letourneau, Elizabeth J.

Sexual Abuse: Journal of Research and Treatment, Vol 14(3), Jul, 2002. pp. 207-223.

Abstract:

This study assessed the reliability and validity of a visual reaction time (VRT) measure of sexual interest (G. G. Abel, J. Huffman, B. Warberg, & C. L. Holland, 1998) and the penile plethysmograph (PPG) with audio stimuli. A sample of 57 sex offenders incarcerated at a high-security military prison completed physiological and self-report measures of sexual interest, including the VRT and the PPG. Results indicated adequate internal consistency for both measures. Convergent validity and an assessment of clinical usefulness for both measures indicated that (a) both measures accurately identified offenders against young boys; (b) the VRT, but not the PPG, significantly identified offenders against adolescent girls; (c) neither measure reached statistical significance in identifying offenders against adult women; and (d) the VRT did not reach statistical significance in identifying offenders against young girls and the PPG did reach statistical significance but in the opposite direction as was expected (i.e., men with female child victims had significantly lower arousal to female child stimuli than did men in other victim choice categories).

Phallometric Nonresponding in Sexual Offenders. 

Looman J.; Abracen J.; Maillet G.; DiFazio R. (1988). 

Sexual Abuse: A Journal of Research and Treatment, Volume 10, Number 4, pp. 325-336(12).

Discriminant and predictive validity of phallometrically measured sexual age and gender preference 

Malcolm, P. B., Andrews, D. A., & Quinsey, V. L. (1993). Journal of Interpersonal Violence, 8, 486-501. 

Sexual offenders against male children: Sexual preferences. 

Marshall, W. L., Barbaree, H. E., & Butt, J. (1988). Behavior Research and Therapy, 26, 383-391. 

Sexual offenders against female children: Sexual preferences for age of victims and type of behaviour. 

Marshall, W. L., Barbaree, H. E., & Christophe, D. (1986). 

Canadian Journal of Behavioural Science, 18, 424-439. 

Assessment, Treatment, and Theorizing About Sex Offenders: Developments during the Past Twenty Years and Future Directions

Marshall, W.L. (1996). Criminal Justice and Behavior, 23 (1), 162-199.

Relationship between MMPI and penile plethysmograph in accused child molesters.

McAnulty, Richard D., et al. Journal of Sex Research, Vol 31(3), 1994. pp. 179-184.

Abstract:

Investigated the relationship between the MMPI and penile plethysmograph in 90 alleged child molesters. Men who had been accused of molesting a prepubertal child were divided into 2 groups based on penile plethysmograph results (Deviant and Non-Deviant Profiles). The MMPI scales were used to predict group membership using discriminant function analysis. The results revealed that the MMPI scores were statistically related to the penile plethysmographic profiles. However, MMPI code types were equally distributed across groups, and no single profile could be described as characteristic of men who exhibited pedophilic arousal using the penile plethysmograph results. Approximately one-third of Ss were misclassified on the basis of MMPI scores alone.

Validity in Phallometric Testing for Sexual Interests in Children: A meta-analytic review.  

McPhail, Ian.  2017. Assessment March 2017

Abstract

Valid assessment of pedohebephilic interests (i.e., sexual interest in children) is fundamental to forensic clinical practice.  Phallometric testing – which measures changes in penile circumference or volume while stimuli depicting different ages and sexual activities are presented – is widely used in clinical and research settings to detect such interests.  This meta-analysis summaries studies comparing sexual offenders against children and various types of controls on phallometric tests for pedohebephilic interests (37 samples; N = 6,785) and studies examining the relationship between phallometric test scores and sexual re-offending (16 samples; N = 2,709).  The findings suggest that several phallometric testing procedures are valid indicators of pedohebephilic interest.  Certain methodological features of phallometric tests were associated with greater validity, such as slide or audio-plus-slide stimuli and z-score based indices.  In addition, phallometric tests for pedohebephilic, pedophilic, and hebephilic interests predicted sexual re-offending which provides further evidence that phallometric test scores are valid indicators of sexual interest in children.  In general, the interpretation of phallometric test scores as indicators of pedohebephilic interests is supported.  

Agreement of Self-Reported and Genital Measures of Sexual Arousal in Men and Women: A Meta-Analysis

Meredith L. Chivers, et al

Archives of Sexual Behavior, 2010, Feb. 39(1): 5-56

Abstract:

Various physiological parameters, such as pupil dilation, heart rate, and galvanic skin response, have been examined as potential objective measures of sexual arousal, but changes in penile erection, assessed using penile plethysmography, are the most specific measure of sexual response in men (Zuckerman, 1971). An objective method of measuring penile erection was developed by Freund (1963). Changes in penile circumference, measured using a gauge placed around the shaft of the penis, or changes in penile volume (assessed using gas displacement in a sealed cylinder placed over the penis) are the most commonly used methods in sexual arousal research. Increases in penile circumference or volume are interpreted as evidence of greater genital sexual arousal. Circumferential and volumetric measurements are highly correlated when men show at least 2.5 mm of penile circumference change in the laboratory (Kuban, Barbaree, & Blanchard, 1999).

Regression to the mean mimicking changes in sexual arousal to child stimuli in pedophiles.

Mokros, Andreas., Habermeyer, Elmar., 

Archives of Sexual Behavior, Vol 45(7), Oct, 2016. pp. 1863-1867.

Abstract

The sexual preference for prepubertal children (pedophilia) is generally assumed to be a lifelong condition. Müller et al. (2014) challenged the notion that pedophilia was stable. Using data from phallometric testing, they found that almost half of 40 adult pedophilic men did not show a corresponding arousal pattern at retest. Critics pointed out that regression to the mean and measurement error might account for these results. Müller et al. contested these explanations. The present study shows that regression to the mean in combination with low reliability does indeed provide an exhaustive explanation for the results. Using a statistical model and an estimate of the retest correlation derived from the data, the relative frequency of cases with an allegedly non-pedophilic arousal pattern was shown to be consistent with chance expectation. A bootstrap simulation showed that this outcome was to be expected under a wide range of retest correlations. A re-analysis of the original data from the study by Müller et al. corroborated the assumption of considerable measurement error. Therefore, the original data do not challenge the view that pedophilic sexual preference is stable.

Accuracy is important—Re: Sensitivity and specificity of the phallometric test for hebephilia.

Moser, Charles. 

Journal of Sexual Medicine, Vol 12(12), Dec, 2015. pp. 2501.

Standardization of penile plethysmography testing in assessment of problematic sexual interests.

Murphy, Lisa., Ranger, Rebekah., Fedoroff, J. Paul., Stewart, Hannah., Dwyer, R. Gregg., Burke, William. 

Journal of Sexual Medicine, Vol 12(9), Sep, 2015. pp. 1853-1861.

Abstract:

Penile plethysmography (PPG) is an objective measure of sexual arousal for men, commonly used to assess sexual arousal to both abnormal (i.e., paraphilic) and normal stimuli. While PPG has become a standard measure in the assessment and treatment of male sex offenders and men with paraphilic interests in both Canada and the United States, there is a lack of standardization of stimulus sets and interpretation of results between sites. The current article critically reviews the current state of the art while highlighting clinical and research efforts that may be undertaken in an attempt to reduce issues arising from lack of standardization across sites. Types and themes of stimulus sets, assessment apparatuses, laboratory preparation, and testing procedures are discussed. The continued development of standardized testing protocol and procedures across multiple international sites continues to be encouraged to promote unified PPG administration and interpretation, thus further enhancing the practical utility of the measurements and decreasing inter‐rater discrepancies and error.

Penile circumference, skin conductance and ranking of child molesters and normals to sexual and non sexual visual stimuli.

Quinsey, V. L., Steinman, C. M., Bergensen, S. G., & Holmes, T. F. (1975). 

Behaviour Therapy, 6, 213-219. 

Sexual preferences among incestuous and nonincestuous child molesters. 

Quinsey, V. L., Chaplin, T. C., & Carrigan, W. F. (1979). Behavior Therapy, 10, 562-565. 

Penile responses of child molesters and normals to descriptions of encounters with children involving sex and violence. 

Quinsey, V. L., & Chaplin, T. C. (1988a). Journal of Interpersonal Violence, 3, 259-274. 

Preventing faking in phallometric assessments of sexual preference.  

Quinsey & Chapman (1988). Annals of the New York Academy of Sciences, Vol 528, Issue 1 49-58, Copyright © 1988 by New York Academy of Sciences . 

Summary:

The experiment was to test the efficacy of a tracking task during a PPG study in which the participants were instructed to attempt to fake or suppress their arousal. Groupdata indicated that subjects could fake inappropriate preferences wheninstructed to do so without the semantic tracking task but could not whenthe task was required. 

An analysis of four sexual offenders’ arousal in the natural environment through the use of a portable penile plethysmograph.

Rea, Jerry A., et al. Sexual Abuse: Journal of Research and Treatment, Vol 10(3), Jul, 1998. pp. 239-255.

Abstract:

Reports the development of a technology for measuring sexual arousal in the natural environment. Ss were 5 male residents of a state hospital for persons with mental retardation, aged 17–37 yrs, who had committed sexual offenses. Exp 1 with 3 of the Ss demonstrated that levels of sexual arousal obtained in the laboratory when a participant was wearing underwear and trousers were similar to arousal levels obtained without underwear and trousers. In Exp 2, 4 Ss’ arousal was measured in the natural environment using a portable penile plethysmograph. Measures were taken in 3 different settings: a setting in which only adults were present, a setting with children present, and a setting with no person other than the data collector present. In each setting, arousal was measured when the data collector was both near and away from the offender. For 3 of 4 offenders, patterns of arousal were consistent with previous laboratory assessments and/or previous offenses. Moreover, arousal was greatest when the data collector was away from the participant. 

A reliable digital plethysmograph for measuring penile circumference change: A preliminary report.

Regan, Maurice, Nelan, James

The Behavior Therapist, Vol 2(3), May-Jun, 1979. pp. 16.

Assessment of deviant arousal in adult male sex offenders with developmental disabilities.

Reyes, Jorge R., et al.  

Journal of Applied Behavior Analysis, Vol 39(2), Sum 2006. pp. 173-188.

Abstract:

Ten individuals, residing in a treatment facility specializing in the rehabilitation of sex offenders with developmental disabilities, participated in an arousal assessment involving the use of the penile plethysmograph. The arousal assessments involved measuring change in penilecircumference to various categories of stimuli both appropriate (adult men and women) and inappropriate (e.g., 8-to 9-year-old boys and girls). This approach extends the existing assessment literature by the use of repeated measurement and single-subject experimental design. Data from these assessments were analyzed to determine if clear and informative outcomes were obtained. Overall, three general patterns of results emerged. Some participants showed differentiated deviant arousal or higher levels of arousal to specific inappropriate stimuli (deviant is a term used in the existing sex-offender literature to describe this type of arousal). Other participants showed undifferentiated deviant arousal, in which case they showed nonspecific arousal to inappropriate stimuli. The remaining participants showed no arousal to inappropriate stimuli but did show arousal to appropriate stimuli. Implications for assessment, treatment, and future directions are discussed. 

The influence of presession factors in the assessment of deviant arousal.

Reyes, Jorge R., et al. 

Journal of Applied Behavior Analysis, Vol 44(4), Win 2011. pp. 707-717.

Abstract:

Three adult male sex offenders with developmental disabilities participated in an evaluation of presession factors that may influence levels of sexual arousal measured with a penile plethysmograph. We evaluated the effects of presession masturbation (1 participant) and arousalsuppression strategies (2 participants). Results showed that presession masturbation lowered arousal levels and both participants suppressed arousal to varying degrees. These outcomes suggest the potential for consideration and manipulation of presession factors as treatment components for sex offenders with developmental disabilities.

Comparison of arousal and preference assessment outcomes for sex offenders with intellectual disabilities.

Reyes, Jorge R.. et al.  

Journal of Applied Behavior Analysis, Vol 50(1), Win 2017. pp. 27-37.

Abstract:

We compared outcomes of arousal and preference assessments for five adult male alleged sexual offenders with intellectual disabilities. Arousal assessments involved the use of the penile plethysmograph to measure changes in penile circumference to both deviant (males and females under the age of 18) and nondeviant (males and females over the age of 18) video clips. Paired‐stimulus preference assessments were arranged to present still images from the video clips used in the arousal assessments. Results showed correspondence between the assessments for four out of the five participants. Implications are discussed for the use of preference assessment methodology as a less intrusive assessment approach for sexual offender assessments. 

Evidence of Penile Plethysmography, Psychological Profiles, Inventories and Other “Not a Pedophile” Character and Opinion Evidence Offered on Behalf of a Defendant in a Child Sexual Abuse Case is Inadmissible Under Daubert v. Merrell Dow Pharmaceutical

Susan K. Smith. Journal of Child Sexual Abuse: research, treatment, and program innovations for victims, survivors, and offenders. Volume: 12 Issue: 3/4, 6/21/2004

Abstract: 

The memorandum reviews the standard of admissibility for scientific evidence as set forth in Daubert v. Merrell Dow Pharmaceuticals, 509 U.S. 579, 113 S. Ct. 2786, 125 L.Ed.2d 469 (1993) and adopted  in State v. Porter, 241 Conn. 57, 698 A.2d 739 (1997). The memorandum reviews the evidence offered by the defendant in a civil child sexual abuse and argues that the defense expert’s conclusions that the defendant is “not a pedophile” based on the results of a sexual behaviors assessment is inadmissible under Daubert. The author argues that the evidence should be excluded either due to a lack of scientific reliability of the tests in the diagnostic context (penile plethysmography), or for a failure to meet Daubert’s “fit” requirement (i.e. MMPI-2 might be scientifically valid but lacks correlation to diagnosis of pedophilia). The memorandum quotes the scientific literature extensively and collects the known cases precluding the admission of penile plethysmography evidence in legal proceedings. The author also argues that the evidence should be excluded as impermissible character evidence.

The penile plethysmograph, Abel Assessment for Sexual Interest, and MSI-II: Are they speaking the same language?

Tong, Dean. American Journal of Family Therapy, Vol 35(3), May-Jun, 2007. pp. 187-202.

Abstract:

This study investigated chiefly whether there was a relationship between sexual interest and sexual arousal in an outpatient sample of men, all of whom were accused of incest within divorces and/or child custody battles. Regardless of the problem of unreliable eyewitness evidence from children, there is always a need for more persuasive evidence in the courtroom to corroborate or impeach allegations of child sexual abuse. The current study under examination is important as validation research in cases where men are accused of incest within contested divorces, visitation disputes, and custody battles. Method: This within-subject correlational study examined the presence or absence of sexual arousal, sexual interest, and cognitive distortions among a random sample of men accused of incest within acrimonious divorces and child custody battles. The study was specific to men accused of molesting their own biological children at the pre-trial, pre-adjudication court phase of litigation. It tested the association, if any, of the Abel Screen VRT, Abel Questionnaire for Men, and MSI-II (independent variables), in relation to the Penile Plethysmograph (dependent variable).