With the start of the new fall semester, students are gearing up for football season, homecoming celebrations and a new round of academic coursework. Yet the first weeks of the fall term are also a time for caution.

The so-called red zone is the period when college students’ risk of being sexually assaulted is highest. According to a 2019 campus climate survey – one of the most recent studies of its size – first-year women are at the highest risk.

In a survey of nine U.S. colleges, over half of campus sexual assaults of first-year students occurred between orientation and Halloween. Data collected by the University of Colorado at Boulder’s Office of Institutional Equity and Compliance in 2021 and 2024 show that the majority of assaults of first-year women students took place in September or October.

Statewide data on self-reported campus sexual assault isn’t collected, but cases associated with several major universities in Colorado in 2026 highlight the issue. In March 2026, Boulder police investigated a series of sexual assaults of underage women at a popular University Hill bar. The women were allegedly drugged, and the bar lost its liquor license and closed permanently.

In July 2026, parents of an Air Force Academy graduate who died by suicide filed a federal lawsuit alleging the university failed to protect their daughter from sexual assault.

As a researcher who studies domestic and interpersonal violence – and a college professor who works with students every day – I’m well aware that estimates of student sexual assault often understate the problem. Students often do not report an assault because they don’t know where to turn, have concerns about confidentiality, don’t trust the institution to respond adequately or are unable to navigate the institution’s resources by themselves. This parallels vast underreporting of sexual assault and abuse in general.

But the number of cases that are reported is already cause for concern.

Why data is so limited

While campus sexual assault is a well-known issue, data on the current state of the problem is limited. Under the Clery Act, federally funded colleges must report annual crime and safety data, but these include sexual assaults only if they are formally reported. If only 16% of victims report their assault through formal channels, this dramatically undercounts students’ experiences of campus sexual assault.

As of 2022, federal law requires universities to conduct campus climate surveys every two years using a standardized tool created by the Department of Education. However, the department has not yet published the survey or the web portal that Congress has charged it with creating.

The best data we do have comes from private groups. The Association of American Universities ran campus climate surveys in 2015 and 2019. WeStat ran a 2024 survey of 10 largely private, largely East Coast universities. But infrequent surveys from private companies are subject to their own discretion and timing, making them less reliable than regular data collected by public agencies.

Risk factors during the red zone

Surveys consistently estimate 1 in 5 college women are assaulted while attending university. Students from marginalized groups, including gender or sexual minorities, are at higher risk.

Risks are also higher for students involved in fraternities or sororities.

First-year women are at the highest risk. These students are particularly vulnerable because they are in a new environment, have fewer friends to watch their back and are often exploring new freedoms, including access to alcohol and other drugs. In addition, many students attend college away from their hometowns where they are separated from their support networks.

Counter to the popular perception that perpetrators are unknown assailants, most sexual assaults are perpetrated by someone known to the victim, and over 21% are committed by an intimate partner.

Alcohol and other drug use creates an especially high risk for sexual assault. While young adults ages 18-25 are drinking less than prior generations, a quarter of surveyed full-time college students reported binge drinking in the previous month. Campus climate surveys show that a majority of surveyed students who were assaulted had voluntarily consumed alcohol and other drugs prior to the assault.

To be clear, these studies are not blaming anyone who has been victimized for drinking. Rather, the research points out how alcohol and other drugs can increase a person’s vulnerability.

Why this matters

College sexual assault substantially affects students’ well-being.

Students who are sexually assaulted are at higher risk for reporting anxiety and depression. Adverse mental and physical health effects of college sexual assault can last for years after graduation.

Sexual assault also negatively affects education outcomes. Students who are assaulted are more likely to have lower grades and learning difficulties – or drop out of college altogether.

Schools receiving federal funding have a legal obligation under Title IX to respond to allegations of sexual assault and sexual harassment. This 1972 federal law prohibits sex-based discrimination in education programs, including on college campuses.

But for students who are victimized during the red zone, accessing care on campus may be particularly challenging. New students, such as freshmen and transfer students, may be less familiar with available resources and their legal rights.

Evidence on interventions

Schools have tried a number of strategies to address the red zone and keep students safe.

Web-based interventions and small-group intensives can reduce victimization, improve students’ self-defense measures, reduce binge drinking and improve bystander intervention awareness. Bystander intervention training teaches students to safely step in when they see unsafe behavior.

These programs help students change their behaviors – such as reducing binge drinking – and combat pervasive “rape myths,” or the belief that victims of sexual assault were “asking for it.” Positive effects can continue years after students complete the training program.

Truly tackling the issue of college sexual assault requires developing new ways to stop individuals who may go on to assault others.

But the focus remains on teaching potential victims how to defend themselves and look out for their peers. Researchers know much, much less about interventions that can prevent people from perpetrating sexual assaults.

In part, this research gap exists because it is difficult to get accurate data on socially undesirable behaviors. Research has shown that survey and interview respondents may misreport their beliefs or behaviors, meaning that people who commit assault are unlikely to admit that on a survey. Certain research methods, such as using written or web-based surveys rather than face-to-face interviews, can elicit more truthful responses.

In Colorado and at colleges across the country, now is the time to keep an eye out for the most vulnerable students. Faculty, staff, students and community members alike can all help build a campus climate where sexual assault is unacceptable, where victims are believed, and where student safety matters.

If you or someone you know has been affected by sexual assault, help is available. RAINN operates a 24/7 helpline at 800-656-HOPE.

Kaitlyn M. Sims is an Assistant Professor at the University of Denver and a criminal justice research fellow at Arnold Ventures.