Sexual Experiences Survey (SES) – Perpetration Version

Abstract

The Sexual Experiences Survey (SES), specifically the Perpetration Version (SES-P), is a comprehensive self-report questionnaire designed to assess the frequency and severity of sexually aggressive acts committed by an individual. Developed by researchers at the University of Michigan, the SES-P is a widely used instrument in psychological and criminological research to determine the prevalence and incidence of sexual aggression. The scale captures a spectrum of coercive behaviors, ranging from verbal pressure and misuse of authority to the use of physical force and drug or alcohol incapacitation, culminating in classifications of sexual contact, attempted rape, sexual coercion, and completed rape.

The SES-P is a valuable clinical and research tool for identifying individuals who may be involved in perpetrating sexual violence, allowing researchers to study the context and consequences of these behaviors. Furthermore, it aids clinicians in assessing the risk of future sexual aggression and informing the development of targeted intervention and prevention programs.

Keywords

Sexual aggression, Sexual perpetration, Sexual violence, Rape, Coercion, Self-report questionnaire, Sexual Experiences Survey, Psychological assessment, Violence risk.

Authors

Mary P. Koss, Christine A. Gidycz, C. J. Oros.

Purpose

The primary purpose of the Sexual Experiences Survey – Perpetration Version (SES-P) is to systematically measure the extent, nature, and intensity of sexually aggressive behavior committed by a respondent. It moves beyond simple documentation of assault by detailing the specific methods of coercion used, such as arguments, abuse of authority, physical threats, or the use of intoxicating substances.

For researchers, the SES-P provides robust data necessary for epidemiological studies on campus or community populations, allowing for accurate estimations of the incidence and prevalence of sexual perpetration. For practitioners, the instrument is instrumental in risk assessment, helping to identify high-risk individuals and providing a foundation for designing effective therapeutic interventions aimed at reducing future acts of sexual aggression.

Construct

The core psychological construct measured by the SES-P is Sexual Perpetration, defined as engaging in unwanted sexual acts against another person through coercive means. The scale operationalizes this construct hierarchically, classifying behaviors based on the severity of the act and the level of coercion employed. The scale establishes four distinct categories of perpetration based on the most severe act reported:

• Sexual Contact (Items 1, 2, or 3): Involving sexual play coerced through pressure, authority, or minor physical force.
• Attempted Rape (Items 4 or 5): Involving attempted intercourse coerced through force or incapacitation (drugs/alcohol).
• Sexual Coercion (Items 6 or 7): Involving completed intercourse coerced through pressure or authority.
• Rape (Items 8, 9, or 10): Involving completed intercourse or other forced sex acts via incapacitation (drugs/alcohol) or significant physical force.

Validity

The SES-P is recognized as a valid measure of sexual perpetration, supported by extensive research. Its validity is established through its ability to accurately measure distinct levels of aggression. The instrument demonstrates strong content validity, as the items directly correspond to behaviors commonly defined as sexual assault or coercion in legal and clinical contexts.

Furthermore, studies have shown that responses on the SES-P correlate meaningfully with other measures of relevant psychological constructs, such as hostile attitudes toward women and adherence to rape myths, demonstrating concurrent validity. The hierarchical scoring system provides a clear, defensible categorization of perpetration severity, further reinforcing its utility in differentiating levels of aggressive sexual behavior.

Reliability

The reliability of the SES-P has been confirmed through various academic studies. Its self-report format, utilizing specific behavioral checklists and frequency counts, minimizes ambiguity and contributes to consistent measurement. While the scale primarily measures lifetime or period prevalence, which inherently affects traditional internal consistency metrics like Cronbach’s alpha (due to the severity hierarchy), the consistency of responses over time (test-retest reliability) for the underlying construct of sexual aggression perpetration has been demonstrated as robust in research samples.

Factor Analysis

While the SES-P is typically scored using a categorical index that reflects the most severe act committed, factor analyses generally support the underlying structure of a single dimension of Sexual Aggression Severity. This suggests that the items load onto a primary factor representing coercive sexual behavior, with item severity following a cumulative pattern. The instrument’s design intentionally creates a hierarchy where engaging in a more severe act (e.g., forced intercourse) implies a higher level of aggression than engaging in a less severe act (e.g., forced fondling), a structure that is upheld by statistical modeling in psychometric research.

Instrument

Test Type: Behavioral Self-report questionnaire

Format: Structured checklist format requiring Yes/No responses regarding specific coercive behaviors, followed by quantitative frequency questions (e.g., 1, 2, 3, 4, 5 or more times) for affirmative answers.

Language Available: English (Original); translations used in various international studies.

Population Group: Individuals assessed for perpetration history, typically focused on male respondents in studies of heterosexual aggression, though the instrument’s principles can be adapted.

Age Group: Adolescents and adults (measuring experiences from age 14 onwards).

Population Details: Widely employed in epidemiological studies among university and college students, but applicable to general population samples for assessing sexual violence perpetration.

Test Methodology: Respondents are asked about specific sexually aggressive acts directed toward others over a defined period (lifetime since age 14 or the last year). Classification of the individual is based on the highest level of severity to which they answer “Yes.”

Keywords

Perpetration scale, Sexual assault measurement, Coercive sexual behavior, Violence risk assessment, Psychological screening, SES-P, University research.

Authors

Author ORCID Identifier: Not specified in the source content.

Affiliation Email addresses: Not specified in the source content.

Correspondence Address: Not specified in the source content (Original developers affiliated with the University of Michigan).

Permissions & Fee and Test Year

The Sexual Experiences Survey was initially published in 1982 (Koss & Oros). It is generally considered an academic instrument available for non-commercial research use with proper attribution. The instrument is publicly documented, and its full text is often reproduced in academic publications and compendia focused on violence measurement.

The instrument can be found on pages 118-120 of Measuring Intimate Partner Violence Victimization and Perpetration: A Compendium of Assessment Tools. The original PDF can be downloaded here: http://www.cdc.gov/ncipc/pub-res/IPV_Compendium.pdf.

Reference’s

• Koss MP, Oros CJ. Sexual Experience Survey: a research instrument investigating sexual aggression and victimization. Journal of Consulting and Clinical Psychology 1982;50:455–457.
• Koss MP, Gidycz CA. Sexual Experience Survey: reliability and validity. Journal of Consulting and Clinical Psychology 1985;53:422–423.
• Koss MP, Gidycz CA, Wisniewski N. The scope of rape: incidence and prevalence of sexual aggression and victimization in a national sample of higher education students. Journal of Consulting and Clinical Psychology 1987;55:162–170.

Items of the Sexual Experiences Survey (SES) – Perpetration Version

IMPORTANT: The following scale items must be preserved in their original language and must not be changed in any way.

On the following pages are questions about your sexual experiences from age 14 on.

1. Have you engaged in sex play (fondling, kissing, or petting, but not intercourse) when she didn’t want to because you overwhelmed her with continual arguments and pressure? Yes No

If No, continue with question 2.

If Yes:

1a. About how many times has it happened (from age 14 on)? 1 2 3 4 5 or more

1b. How many times last school year (September to September)? 0 1 2 3 4 5 or more

2. Have you engaged in sex play (fondling, kissing, or petting but not intercourse) when she didn’t want to because you used your position of authority (boss, teacher, camp counselor, supervisor) to make her? Yes No

If No, continue with question 3.

If Yes:

2a. About how many times has it happened (from age 14 on)? 1 2 3 4 5 or more

2b. How many times last school year (September to September)? 0 1 2 3 4 5 or more

3. Have you engaged in sex play (fondling, kissing, or petting but not intercourse) when she didn’t want to because you threatened or used some degree of physical force (twisting her arm, holding her down, etc.) to make her? Yes No

If No, continue with question 4.

If Yes:

3a. About how many times has it happened (from age 14 on)? 1 2 3 4 5 or more

3b. How many times last school year (September to September)? 0 1 2 3 4 5 or more

4. Have you attempted sexual intercourse (get on top of her, attempt to insert your penis) when she didn’t want to by threatening or using some degree of force (twisting her arm, holding her down, etc.), but intercourse did not occur? Yes No

If No, continue with question 5.

If Yes:

4a. About how many times has it happened (from age 14 on)? 1 2 3 4 5 or more

4b. How many times last school year (September to September)? 0 1 2 3 4 5 or more

5. Have you attempted sexual intercourse (get on top of her, attempt to insert your penis) when she didn’t want to by giving her alcohol or drugs, but intercourse did not occur? Yes No

If No, continue with question 6.

If Yes:

5a. About how many times has it happened (from age 14 on)? 1 2 3 4 5 or more

5b. How many times last school year (September to September)? 0 1 2 3 4 5 or more

6. Have you engaged in sexual intercourse when she didn’t want to because you overwhelmed her with continual arguments and pressure? Yes No

If No, continue with question 7.

If Yes:

6a. About how many times has it happened (from age 14 on)? 1 2 3 4 5 or more

6b. How many times last school year (September to September)? 0 1 2 3 4 5 or more

7. Have you engaged in sexual intercourse when she didn’t want to because you used your position or authority (boss, teacher, camp counselor, supervisor) to make her? Yes No

If No, continue with question 8.

If Yes:

7a. About how many times has it happened (from age 14 on)? 1 2 3 4 5 or more

7b. How many times last school year (September to September)? 0 1 2 3 4 5 or more

8. Have you engaged in sexual intercourse when she didn’t want to because you gave her alcohol or drugs? Yes No

If No, continue with question 9.

If Yes:

8a. About how many times has it happened (from age 14 on)? 1 2 3 4 5 or more

8b. How many times last school year (September to September)? 0 1 2 3 4 5 or more

9. Have you engaged in sexual intercourse when she didn’t want to because you threatened or used some degree of physical force (twisting her arm, holding her down, etc.) to make her? Yes No

If No, continue with question 10.

If Yes:

9a. About how many times has it happened (from age 14 on)? 1 2 3 4 5 or more

9b. How many times last school year (September to September)? 0 1 2 3 4 5 or more

Have you engaged in sex acts (anal or oral intercourse or penetration by objects other than the penis) when she didn’t want to because you threatened her or used some degree of physical force (twisting her arm, holding her down, etc.) to make her? Yes No

If No, continue with question 11.

If Yes:

10a. About how many times has it happened (from age 14 on)? 1 2 3 4 5 or more

10b. How many times last school year (September to September)? 0 1 2 3 4 5 or more

10. Did you answer “Yes” to any of the questions 1-10? Yes No

If Yes:

11a. Look back to the questions 1-10 in this section. What is the highest question number to which you marked “Yes”? 1 2 3 4 5 6 7 8 9 10