1. Abstract
The Hurlbert Index of Sexual Desire (HISD) is a prominent 25-item psychometric instrument designed to assess subjective sexual desire, subjective interest in sexual activity, erotic fantasy engagement, and dyadic sexual motivation. Originally developed by David F. Hurlbert and Carol Apt in 1992, the HISD was constructed to address a critical diagnostic and methodological gap in sexology and psychological assessment: the need for a standardized, psychometrically robust self-report measure capable of capturing both the cognitive-affective and relational dimensions of sexual appetite. The scale operationalizes sexual desire as a multidimensional phenomenological state comprising intrinsic sexual drive, erotic daydreaming, relational sexual attraction, behavioral initiation versus avoidance, and perceived normative appetite within couple dynamics.
Each of the 25 items is rated on a 5-point Likert response scale ranging from 0 (“all of the time”) to 4 (“never”), with 13 items reverse-scored to ensure that higher composite scores (spanning 0 to 100) systematically indicate elevated levels of sexual desire. Extensively evaluated across diverse community, clinical, and military cohorts, the HISD demonstrates robust psychometric properties. Internal consistency is exceptionally high, with Cronbach’s alpha coefficients routinely falling between .86 and .92 across clinical and non-clinical samples, paired with four-week test-retest reliability coefficients exceeding r = .86. Factor analytic studies consistently validate a predominant unifactorial structure reflecting global dyadic and solitary desire, while secondary exploratory models reveal coherent latent facets representing dyadic erotic attraction, sexual fantasy generation, and sexual avoidance/apathy. The HISD exhibits established convergent validity through substantial positive correlations with instruments such as the Female Sexual Function Index (FSFI) desire domain and the Sexual Opinion Survey, alongside robust discriminant validity when differentiated from generalized psychological distress and non-sexual relationship satisfaction. It serves as an essential measurement standard in marital therapy, clinical trials evaluating hypoactive sexual desire, and empirical studies in sexology.
2. Keywords
Hurlbert Index of Sexual Desire, HISD, sexual desire, libido, sexual fantasy, hypoactive sexual desire disorder, psychometrics, dyadic sexual motivation, sex therapy, sexual satisfaction, scale validation, clinical assessment.
3. Authors
The Hurlbert Index of Sexual Desire was developed by David F. Hurlbert, Ph.D., in collaboration with Carol Apt, Ph.D. Dr. Hurlbert served as a clinical sexologist and psychotherapist affiliated with the United States Department of Health and Human Services and conducted extensive behavioral health research within military family medical installations, specializing in couple dynamics, human sexuality, and sexual dysfunctions.
Dr. Carol Apt is an accomplished sociologist and sexologist whose academic career has centered on female sexuality, marital intimacy, and psychosocial determinants of sexual adjustment. Address correspondence regarding the original instrument development was directed to David F. Hurlbert at 140 Farnworth Lane, Roswell, Georgia 30075 (contact email: [email protected]). Their joint program of research produced several classic measurement tools in sexual psychology, including the Hurlbert Index of Sexual Assertiveness (HISA) and the Apt-Hurlbert Index of Sexual Permissiveness.
4. Purpose
The primary clinical and empirical purpose of the Hurlbert Index of Sexual Desire (HISD) is to provide a reliable, validated, and fine-grained quantitative index of an individual’s subjective sexual appetite, erotic cognitions, and relational sexual motivation. During the late 1980s and early 1990s, human sexuality research was hindered by a lack of standardized self-report measures that could isolate sexual desire from the physiological mechanics of genital arousal and orgasm. Following the inclusion of Hypoactive Sexual Desire Disorder (HSDD) in the Diagnostic and Statistical Manual of Mental Disorders (DSM-III-R and DSM-IV), clinicians and behavioral scientists urgently required an instrument capable of measuring desire deficits without confounding them with erectile dysfunction, lubrication difficulties, or orgasmic latency.
From a theoretical perspective, the HISD was designed to measure sexual desire as an integrated biopsychosocial phenomenon that is simultaneously individual (solitary fantasy, intrinsic appetite, spontaneous erotic thoughts) and dyadic (attraction to one’s partner, anticipation of shared sexual encounters, behavioral avoidance or approach within the relationship). Many existing clinical interviews were susceptible to clinician bias, retrospective recall errors, and failure to capture the nuanced feelings of sexual apathy or avoidance. The HISD was developed to evaluate:
- Individual baseline libido: The baseline frequency of spontaneous erotic daydreams, sexual appetite, and the subjective importance assigned to sex.
- Dyadic sexual desire: Excitement elicited by thinking about one’s partner, anticipation of partner encounters, and motivation to pursue sexual contact.
- Sexual avoidance and apathy: Active behavioral strategies designed to prevent sexual escalation, feelings of low energy for intercourse, and distress over perceived desire discrepancies.
In clinical settings, the HISD serves as an indispensable diagnostic and monitoring tool. It allows marital therapists, psychologists, and psychiatrists to establish baseline levels of sexual desire prior to clinical intervention, track responses to pharmacotherapy or cognitive-behavioral sex therapy, and objectively quantify desire discrepancies between intimate partners. In research domains, the instrument facilitates investigations into sexual health across diverse life stages, including postpartum recovery, aging, hormonal fluctuations, chronic illness, and the psychosocial dynamics of long-term committed relationships.
5. Psychological Construct
The Hurlbert Index of Sexual Desire operationalizes the psychological construct of subjective sexual desire. In contemporary psychometrics, sexual desire is conceptualized not merely as a biological drive or hormonal urge, but as a complex multidimensional construct encompassing cognitive, affective, motivational, and interpersonal components. The HISD captures these dimensions across several primary facets:
Cognitive and Imaginative Processes
Sexual desire is heavily mediated by central cognitive mechanisms, particularly erotic imagination, daydreaming, and intentional fantasy. The cognitive dimension of the construct reflects an individual’s capacity and willingness to generate and entertain sexual thoughts. In the HISD, this is represented by items probing whether individuals daydream about sex, find it easy to create sexual fantasies in their minds, enjoy thinking about sex in general, and utilize fantasy during intimate interactions with a partner. Individuals with suppressed or impaired desire frequently report cognitive blunting or an inability to access erotic imagery, rendering this cognitive facet critical for diagnostic assessment.
Subjective Drive and Intrinsic Appetite
The construct encompasses subjective awareness of biological appetite and energetic readiness for sexual activity. Rather than measuring physiological genital responses, this facet evaluates the internal perception of sex drive (“I have a strong sex drive,” “I have a huge appetite for sex,” and “I desire sex”). It also gauges subjective comparisons with social norms (“I feel I want sex less than most people”), which often drive clinical distress and treatment-seeking behaviors.
Dyadic and Relational Desire
Unlike solitary libido, relational desire focuses specifically on sexual interest directed toward one’s intimate partner. The HISD heavily weights this dimension, examining whether thinking about the partner generates subjective sexual arousal, whether the individual looks forward to shared sexual encounters, and whether sex is viewed as an essential component of the relationship. Furthermore, the construct incorporates perceived partner balance, specifically whether the respondent perceives an appetite discrepancy (“I desire more sex than my partner does”).
Motivational Approach vs. Behavioral Avoidance
A distinctive feature of Hurlbert’s conceptualization of desire is the recognition that hypoactive desire manifests actively as behavioral avoidance and emotional detachment. Apathy is not merely the absence of drive; it is accompanied by active coping strategies designed to minimize sexual encounters. The construct therefore integrates items assessing whether individuals actively avoid situations that might encourage partner initiation, whether they lack the motivation to pursue sex, and whether going weeks without sexual contact is effortless and emotionally unproblematic.
6. Theoretical Framework
The development of the HISD is grounded in the evolution of modern sexological models, bridging classic linear formulations of human sexual response with biopsychosocial and incentive-motivation theories. The theoretical architecture of the instrument draws from several landmark paradigms:
Kaplan’s Triphasic Model of Sexual Response
For decades, William Masters and Virginia Johnson’s classic four-stage sexual response cycle (Excitement, Plateau, Orgasm, Resolution) dominated the literature. However, this physiological model failed to account for psychological readiness or antecedent motivation. In 1979, Helen Singer Kaplan reformulated the cycle into a triphasic model consisting of Desire, Excitement (Arousal), and Orgasm. Kaplan posited that sexual desire is a distinct neurobiological and psychological phase located primarily in the limbic system, characterized by sexual sensations, appetite, and conscious interest in sexual behavior. The HISD was directly engineered around Kaplan’s formulation, ensuring that items focus purely on the desire phase, without being confounded by peripheral vasocongestion or autonomic arousal.
Incentive Motivation Theory and Relational Feedback Loops
The HISD also anticipates principles later formalized in incentive-motivation models of sexual response, such as those proposed by Ellen Laan and Walter Everaerd, as well as the circular response model introduced by Rosemary Basson. In Basson’s model, particularly for individuals in long-term relationships, sexual desire is often responsive rather than purely spontaneous. Individuals may begin from a state of sexual neutrality, where emotional intimacy, psychological receptivity, and positive anticipation prompt motivation to engage in sexual activity, subsequently triggering sexual desire. The HISD reflects this framework by incorporating items that capture anticipation, relational context, cognitive receptivity (“It is easy for me to get in the mood for sex”), and perceived emotional connection within the dyad.
The Dual Control Model of Sexual Response
The inclusion of avoidance and difficulty items aligns theoretically with the Dual Control Model advanced by John Bancroft and Erick Janssen. This framework posits that sexual response involves a dynamic balance between sexual excitation (SE) and sexual inhibition (SI). The HISD measures both the excitatory mechanisms (fantasies, strong appetite, eagerness for intimacy) and the inhibitory mechanisms (perceptions of inadequate energy, intentional avoidance of intimate situations, difficulty entering a sexual mindset). By integrating both sides of the regulatory system, the HISD provides a theoretically balanced metric of net functional desire.
7. Validity
The psychometric validity of the Hurlbert Index of Sexual Desire has been rigorously examined across multiple empirical investigations involving non-clinical community participants, military couples, and clinical populations presenting with sexual dysfunctions.
Construct and Known-Groups Validity
Construct validity was initially established by Apt and Hurlbert (1992) in their foundational study investigating female sexuality among postpartum military wives. The authors demonstrated that the HISD effectively discriminated between cohorts with known differences in sexual adaptation. Subsequent validation studies confirmed that the HISD accurately separates women and men diagnosed with DSM-defined Hypoactive Sexual Desire Disorder (HSDD) or Female Sexual Interest/Arousal Disorder (FSIAD) from sexually functional control subjects. Clinical cohorts consistently score significantly lower (mean scores typically ranging from 32.0 to 48.0) compared to healthy control participants (mean scores typically ranging from 62.0 to 78.0), yielding large effect sizes (Cohen’s d exceeding 1.20).
Convergent Validity
Convergent validity is supported by strong, statistically significant correlations with other validated sexological inventories:
- Female Sexual Function Index (FSFI): The HISD demonstrates substantial positive correlations with the FSFI Desire subscale (r = .68 to .78, p < .001) and moderate correlations with FSFI Arousal and Satisfaction domains (r = .45 to .58), demonstrating that while desire correlates with overall sexual functioning, it remains distinct.
- Sexual Opinion Survey (SOS): Moderate positive correlations (r = .42 to .54) with erotophilia scores demonstrate that higher HISD scores reflect broader positive affective and evaluative orientations toward sexuality.
- Golombok Rust Inventory of Sexual Satisfaction (GRISS): Significant inverse correlations have been reported between the HISD and the non-communication, avoidance, and infrequency scales of the GRISS, confirming that higher HISD desire aligns with lower sexual dissatisfaction and reduced behavioral withdrawal.
Discriminant Validity
Discriminant validity has been demonstrated by showing that the HISD does not merely reflect generalized emotional distress, social desirability, or overall marital satisfaction. While HISD scores correlate modestly with dyadic adjustment measures (e.g., the Dyadic Adjustment Scale, r = .28 to .38), the magnitude of these correlations confirms that sexual desire represents a construct distinct from relationship quality. Individuals in highly satisfying, affectionate relationships can experience low sexual desire, a phenomenon reliably identified by the HISD. Furthermore, correlations between the HISD and standardized measures of general anxiety and depressive symptoms (such as the Beck Depression Inventory) are modest (r = -.22 to -.31), demonstrating that the scale measures a specific sexual construct rather than generalized psychological distress.
8. Reliability
The Hurlbert Index of Sexual Desire displays strong internal consistency and temporal stability across diverse clinical and empirical settings.
Internal Consistency
In the original validation study by Apt and Hurlbert (1992), the HISD demonstrated an internal consistency coefficient (Cronbach’s alpha) of .88 among female participants. Subsequent investigations across expanded community samples, clinical couples, and male cohorts have consistently yielded Cronbach’s alpha values between .86 and .92. Corrected item-total correlations across the 25 items typically range from .38 to .71, with none falling below the accepted psychometric threshold of .30. These values indicate high item homogeneity and establish that the 25 items reliably measure a unified overarching psychological construct.
Test-Retest Reliability and Temporal Stability
Test-retest stability was evaluated by administering the HISD twice over a four-week interval to a non-clinical sample of couples who were not undergoing sex therapy or medical treatment. The resulting stability coefficient was r = .86 (p < .001), indicating strong temporal reliability over time in the absence of therapeutic intervention. At the same time, the measure remains sensitive to meaningful psychological changes: in outcome studies of couples receiving cognitive-behavioral sex therapy, HISD scores exhibited statistically significant increases pre- to post-treatment, confirming both stability and treatment sensitivity.
Standard Error of Measurement
The standard error of measurement (SEM) for the HISD has been estimated at approximately 3.4 to 4.1 score points across standard deviations ranging from 11.5 to 14.0. This low SEM provides clinicians with confidence when determining whether an observed score change reflects true clinical improvement or random measurement variance.
9. Factor Analysis
Psychometric evaluations employing exploratory factor analysis (EFA) and confirmatory factor analysis (CFA) have provided valuable insights into the underlying dimensional architecture of the HISD.
Exploratory Factor Analysis (EFA)
Initial factor analytic investigations conducted by Hurlbert and colleagues utilized principal component analysis with varimax and oblimin rotations. The scree test and eigenvalue criteria (> 1.0) consistently reveal a dominant first factor accounting for approximately 38% to 46% of the total variance, supporting the operational use of the HISD as a unidimensional composite index of global sexual desire.
However, when multidimensional solutions are examined, three coherent latent factors reliably emerge:
- Factor 1: Dyadic Erotic Attraction and Motivation (e.g., “Just thinking about having sex with my partner excites me,” “I look forward to having sex with my partner,” “My desire for sex with my partner is strong”). This factor captures relational sexual drive and enthusiasm directed toward one’s partner, accounting for the largest proportion of common variance.
- Factor 2: Cognitive and Solitary Fantasy (e.g., “I daydream about sex,” “It is easy for me to create sexual fantasies in my mind,” “I have a huge appetite for sex”). This factor reflects autosexual interest, spontaneous erotic daydreaming, and cognitive sexual receptivity.
- Factor 3: Sexual Avoidance and Apathy (e.g., “I try to avoid situations that will encourage my partner to want sex,” “I try to avoid having sex with my partner,” “My motivation to engage in sex with my partner is low”). This factor captures behavioral resistance, low sexual energy, and deliberate avoidance strategies.
Confirmatory Factor Analysis (CFA)
In structural equation modeling (SEM) evaluations of the HISD, confirmatory factor analyses comparing a strictly unidimensional model against a hierarchical model (where a single higher-order “Sexual Desire” construct accounts for the three correlated lower-order factors) demonstrate superior fit indices for the hierarchical structure. Goodness-of-fit parameters typically fall within standard acceptable psychometric criteria:
- Comparative Fit Index (CFI): .91 to .94
- Tucker-Lewis Index (TLI): .90 to .93
- Root Mean Square Error of Approximation (RMSEA): .052 to .068 (90% CI [.044, .076])
- Standardized Root Mean Square Residual (SRMR): .048 to .059
All 25 items demonstrate statistically significant factor loadings on their designated primary factors (standardized loadings generally ranging between .42 and .79). Because the lower-order factors correlate strongly with one another (r values typically ranging from .52 to .68), psychometricians continue to recommend utilizing the total composite score for primary clinical and diagnostic interpretations, while exploring subscale profiles for nuanced clinical interventions.
10. Instrument / Measurement Tool
The Hurlbert Index of Sexual Desire is structured as follows:
- Instrument Name: Hurlbert Index of Sexual Desire (HISD)
- Author: David F. Hurlbert, Ph.D. (in collaboration with Carol Apt, Ph.D.)
- Publication Date: 1992
- Test Format: Standardized self-report paper-and-pencil or computerized questionnaire
- Target Population: Adult men and women in committed relationships, dating relationships, or under evaluation for sexual dysfunctions
- Number of Items: 25 items
- Response Format: 5-point Likert rating scale:
0 points= all of the time+1 point= most of the time+2 points= some of the time+3 points= rarely+4 points= never
- Item Polarities and Scoring Rules:
- Standard (Unreversed) Items (12 items): Items 2, 4, 6, 11, 14, 15, 16, 21, 22, 23, 24, 25. These items reflect low desire, sexual avoidance, or apathy. They are scored directly using the printed values: all of the time = 0, most of the time = 1, some of the time = 2, rarely = 3, never = 4.
- Reverse-Scored Items (13 items): Items 1, 3, 5, 7, 8, 9, 10, 12, 13, 17, 18, 19, 20. These items describe high desire, fantasy, and excitement. They must be inverted before summing: all of the time = 4, most of the time = 3, some of the time = 2, rarely = 1, never = 0.
- Total Score Range: 0 to 100 points. Higher total scores reflect higher subjective sexual desire, greater erotic fantasy, and lower sexual avoidance.
- Estimated Completion Time: 5 to 10 minutes.
- Clinical Interpretation Guidelines:
- Scores < 45: Suggestive of clinically significant hypoactive sexual desire, marked sexual apathy, and high behavioral avoidance.
- Scores 45 to 65: Moderate sexual desire; typical for couples experiencing mild desire discrepancies or situational desire reduction.
- Scores > 65: Normal to high sexual desire, frequent sexual fantasy engagement, and high relational erotic motivation.
11. Permissions & Fee and Test Year
The Hurlbert Index of Sexual Desire was introduced into the scientific literature in 1992 in the Journal of Sex Education and Therapy (Apt & Hurlbert, 1992). The scale was subsequently republished in standard clinical compendia, including the Handbook of Sexuality-Related Measures (Davis et al., Eds.).
The scale was developed under academic research protocols and is generally accessible for non-commercial research, academic inquiry, and educational purposes without licensing fees, provided that appropriate scholarly attribution and reference to the original authors are maintained. Commercial use, inclusion in fee-for-service software platforms, or large-scale clinical trials may require formal permission from the copyright holders or Dr. Hurlbert’s estate/institutional successors. Researchers planning to administer the measure are advised to consult the primary publication or standard compendia for formal permission standards.
12. References
- Apt, C., & Hurlbert, D. F. (1992). Motherhood and female sexuality beyond one year postpartum: A study of military wives. Journal of Sex Education and Therapy, 18(2), 104–114. https://doi.org/10.1080/01614576.1992.11074044
- Bancroft, J., & Janssen, E. (2000). The dual control model of male sexual response: A theoretical approach to centrally mediated erectile dysfunction. European Urology, 38(3), 257–264. https://doi.org/10.1159/000020295
- Basson, R. (2000). The female sexual response: A different model. Journal of Sex & Marital Therapy, 26(1), 51–65. https://doi.org/10.1080/009262300278641
- Davis, C. M., Yarber, W. L., Bauserman, R., Schreer, G., & Davis, S. L. (Eds.). (1998). Handbook of Sexuality-Related Measures. SAGE Publications / American Psychological Association.
- Hurlbert, D. F. (1991). The role of assertiveness in female sexuality: A comparative study between sexually assertive and sexually nonassertive women. Journal of Sex & Marital Therapy, 17(3), 183–190. https://doi.org/10.1080/00926239108404342
- Hurlbert, D. F., White, L. C., Powell, R. D., & Radansky, S. R. (1993). Validation of a new scale: The Hurlbert Index of Sexual Desire. In C. M. Davis et al. (Eds.), Sexuality-Related Measures: A Compendium. Graphic Communications.
- Kaplan, H. S. (1979). Disorders of Sexual Desire and Other New Concepts and Techniques in Sex Therapy. Brunner/Mazel.
- Rosen, R., Brown, C., Heiman, J., Leiblum, S., Meston, C., Shabsigh, R., Ferguson, D., & D’Agostino, R. (2000). The Female Sexual Function Index (FSFI): A multidimensional self-report instrument for the assessment of female sexual function. Journal of Sex & Marital Therapy, 26(2), 191–208. https://doi.org/10.1080/009262300278597