Sexual Experiences Survey (SES)—Victimization Version

Abstract

The Sexual Experiences Survey (SES)—Victimization Version is a widely utilized psychological scale designed to measure the lifetime prevalence and incidence of female sexual victimization. Developed by Koss and colleagues, this instrument employs a hierarchical classification system to categorize experiences based on the severity of aggression used, ranging from verbal pressure and misuse of authority (coercion) to physical force, threats, or incapacitation via drugs/alcohol (attempted rape and rape). It is particularly noted for its use in epidemiological studies among college populations to accurately assess the scope of sexual violence.

Keywords

Sexual victimization, sexual aggression, sexual coercion, rape, attempted rape, prevalence, screening, college students, higher education.

Authors

Mary P. Koss, Christine A. Gidycz, Carol J. Oros, Nancy Wisniewski

Purpose

The primary purpose of the SES-Victimization Version is to provide a standardized, behaviorally specific measure for assessing the scope of unwanted sexual experiences. By focusing on concrete behaviors and coercive tactics rather than relying on subjective legal definitions, the scale minimizes ambiguity and improves reporting accuracy regarding sexual assault incidents.

The instrument is crucial for epidemiological research, allowing investigators to quantify different levels of aggression and determine the prevalence rates of various forms of victimization, thereby informing prevention and intervention strategies within campus and community settings.

Construct

The SES measures the construct of sexual victimization, defined hierarchically by the degree of force, threat, or psychological pressure employed by the perpetrator. The scale delineates four primary, mutually exclusive categories of severity, scoring respondents based on the most severe incident reported:

• Sexual Contact: Involves unwanted fondling or petting due to continual arguments, pressure, or misuse of authority.
• Sexual Coercion: Involves unwanted sexual intercourse due to continual arguments, pressure, or misuse of authority.
• Attempted Rape: Involves attempted sexual intercourse using threats, physical force, or incapacitation via drugs/alcohol, where penetration did not occur.
• Rape: Involves completed sexual intercourse or other forced penetration acts using physical force, threat, or incapacitation via drugs/alcohol.

Validity

The SES demonstrates strong face validity and content validity because it uses explicit, behaviorally anchored descriptions of aggressive acts rather than ambiguous terminology. This approach ensures that the questions directly measure the specific behaviors associated with sexual aggression.

Construct validity is supported by the hierarchical nature of the scoring system. Studies have consistently shown that the categorization scheme—from sexual contact up to rape—reflects an increasing continuum of severity, coercion, and physical invasiveness, which aligns with theoretical models of sexual violence.

Reliability

The reliability of the Sexual Experiences Survey has been established through initial validation studies, confirming the instrument’s utility as a stable measure of sexual victimization history. The internal consistency of the items, though not always reported via standard metrics like Cronbach’s alpha in the original papers, is inherent in its design, which aims for mutual exclusivity in the hierarchical classification.

Factor Analysis

While the SES is typically scored based on a hierarchical, severity-based model rather than a traditional factor structure, the items inherently cluster around types of coercive mechanisms (e.g., verbal pressure, authority misuse, physical force, drug-induced incapacitation). The primary utility of the scale lies in its ability to classify respondents into distinct severity levels, which serves as a categorical structure replacing a dimensional factor analysis model.

Instrument

Test Type: Self-report retrospective questionnaire; Screening tool

Format: Dichotomous (Yes/No) initial response for 11 primary items, followed by conditional frequency counts for lifetime and recent (last school year) occurrences.

Language Available: English (Original)

Population Group: Female Respondents (often studied in relation to male perpetrators, as reflected in the item wording).

Age Group: 14 years and older (items ask about experiences from age 14 on).

Population Details: Historically validated and widely used in samples of undergraduate and higher education students, though applicable to general populations.

Test Methodology: Respondents are scored based on the most severe affirmative response, classifying them into the highest level of sexual victimization reported (Sexual Contact, Sexual Coercion, Attempted Rape, or Rape).

Keywords

Victimization scale, sexual assault, Koss, Gidycz, prevalence study, psychological assessment, intimate partner violence.

Authors

Author ORCID Identifier: Not provided in source material.

Affiliation Email addresses: Not provided in source material.

Correspondence Address: Not provided in source material.

Permissions & Fee and Test Year

The original instrument was first published and validated in the early 1980s (Koss & Oros, 1982). Users should consult the primary authors (M.P. Koss) or the institutional review board responsible for the compendium where the scale was published for specific licensing and permission details for use.

The instrument can be found on pages 41-43 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, 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.

• 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.

Items of the Sexual Experiences Survey (SES)—Victimization 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 given in to sex play (fondling‚ kissing‚ or petting‚ but not intercourse) when you didn’t want to because you were overwhelmed by a man’s 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 had sex play (fondling‚ kissing‚ or petting but not intercourse) when you didn’t want to because a man used his position of authority (boss‚ teacher‚ camp counselor‚ supervisor) to make you? 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 had sex play (fondling‚ kissing‚ or petting but not intercourse) when you didn’t want to because a man threatened or used some degree of physical force (twisting your arm‚ holding you down‚ etc.) to make you?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 had a man attempt sexual intercourse (get on top of you‚ attempt to in‎sert his penis) when you didn’t want to by threatening or using some degree of force (twisting your arm‚ holding you 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 had a man attempt sexual intercourse (get on top of you‚ attempt to in‎sert his penis) when you didn’t want to by giving you 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 given in to sexual intercourse when you didn’t want to because you were overwhelmed by a man’s 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 had sexual intercourse when you didn’t want to because a man used his position of authority (boss‚ teacher‚ camp counselor‚ supervisor) to make you? 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 had sexual intercourse when you didn’t want to because a man gave you 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 had sexual intercourse when you didn’t want to because a man threatened or used some degree of physical force (twisting your arm‚ holding you down‚ etc.) to make you? 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

10. Have you had sex acts (anal or oral intercourse or penetration by objects other than the penis) when you didn’t want to because a man threatened you or used some degree of physical force (twisting your arm‚ holding you down‚ etc.) to make you?

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

11. 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