In an article recently published in Social Forces, Jonathan Bearak of New York University investigates the sexual risk-taking behaviors of undergraduate students, specifically their use of contraception (condoms) during casual sexual encounters (hookups).  Bearak is particularly interested in how these behaviors change over the course of a four-year education.

Prior research suggests that:

• Students use condoms inconsistently. 
• While health behavior is generally positively associated with socio-economic status, higher SES adolescents in relationships actually tend to use condoms less than their lower SES counterparts.
• Contraceptive practices may be affected by relationship type (romantic relationship vs. hookup).
• Contraceptive practices may be affected by peers and the college environment.

Bearak analyzed data on more than 10,000 hookups reported by students in the Online College Social Life Survey (2005 and 2011).  His sample is restricted to self-identifying heterosexual students.  Respondent' mother's educational attainment is used as a proxy for family SES.  He found that:

• Students can be grouped into three categories: a small group who avoids intercourse altogether, a larger group who has sex only in a relationship, and a larger group still who engages in hookups (intercourse outside of a relationship).
• Among students who have had intercourse, 57 percent of freshmen, and fully two-thirds of seniors reported engaging in intercourse outside of a relationship.
• The odds of intercourse when hooking up double between the freshman and senior years.
• When coitus occurs during hookups, the odds of condom use decrease by half by the sophomore year.
• The entirety of the decline in condom use is accounted for by lower-SES students adopting the behavior exhibited by higher-SES students at the onset of college.
• Change in female behavior is somewhat sensitive to a school's gender composition: the odds of intercourse increase more at schools with above average ratios of females to males.  School gender composition does not appear to affect odds of intercourse for men.
• The decline in condom use is especially pronounced in cases where the partner attended the respondent's college.

He concludes that:

"the college environment substantially affects undergraduate sexual behavior. [...] College may not discourage condom use directly, but rather, expose undergraduates to a pool of potential partners with whom they feel safer or otherwise place them in social situations that do not encourage condom use. [An] interpretation of these findings is that becoming embedded within certain environments encourages students to take on the role of high SES individuals, among whom condom use appears less normative.  Consistent with this, changes in condom use rates as undergraduates progress through college decline as low SES students adopt the lower rates of condom use of their high SES peers.  One possibility is that changing perceptions of safety and trust affect condom use, but students may adopt roles irrespective of these concerns, if they ascribe these behaviors to individuals they wish to or feel pressure to emulate."

Read more:
http://www.npr.org/2015/04/08/398224608/why-is-condom-use-suddenly-dropping-among-college-sophomores
http://muse.jhu.edu/journals/social_forces/v093/93.2.bearak.pdf

TeachingwithData.org resources:
Gender and Racial Differences in Teens' Attitudes about Sexuality: A Data-Driven Learning Guide (http://www.teachingwithdata.org/resource/3445)
Guttmacher (http://www.teachingwithdata.org/resource/3139)