California Sunday became the first state to adopt “yes means yes” legislation to curb sexual assault reports on college campuses. Contrary to the “no means no” refrain, the bill defines consent as "an affirmative, conscious and voluntary agreement to engage in sexual activity." This is meant to encompass scenarios typically excluded by the “no” policy such as when a participant is intoxicated, unconscious or asleep during an attack.

While affirmative consent has been criticized for governing what goes on in student’s bedrooms, proponents say the new language surrounding consent reduces the ambiguity that can lead to violent sexual encounters. The standard extends to a college’s disciplinary boards that investigate sexual misconduct cases on campus. For instance, instead of asking a victim if he or she said “no” during the alleged attack, the new line of questioning will be directed toward the alleged attacker. Slate reported example questions could be, "Did she want to have sex with you?" or "Did she want to do everything you two did?"

But even under the new standard, understanding which circumstances qualify as assault may be hard to identify. Yale University changed its sexual misconduct policy in 2011 to include affirmative consent. At the time, the Ivy League school was under federal investigation for violating Title IX, a federal anti-discrimination law passed in 1972 that encompasses sexual discrimination. Two years later, to clarify "Yes Means Yes," the school published a set of hypothetical scenarios of sexual misconduct that could lead to a student’s expulsion, Yale’s Office of the Provost wrote in a memo. One example: “As Harper initiates sex, Sidney says, ‘This is a bad idea’ and begins to cry, but embraces Harper and the two proceed to have sex.”

While the California bill is a historic step on the state legislative level, affirmative consent -- as “yes means yes” is commonly referred to -- has been part of college campus sexual misconduct policies for years. But the revised language that defines consent does not necessarily mean sexual assaults have decreased.

The National Center for Higher Education Risk Management, an umbrella organization that advises colleges on campus health and safety issues, said more than 800 colleges have adopted its consent-based model policy where consent can “can be given by words or actions” and where “silence, in and of itself, cannot be interpreted as consent.”

Antioch College, a small liberal arts college in Ohio, pioneered the “yes-means-yes” concept when it implemented its Sexual Offense Prevention Policy in 1991. According to this policy, consent means “verbally asking and verbally giving or denying consent for all levels of sexual behavior.”

At the time, the policy took the national stage on NBC’s “Saturday Night Live” where it was mocked in a skit called “Is It Date Rape?” The parody game show involved participants acting out scenarios found in the school’s sexual offense policy.

“If you think about it not in the mocking ‘SNL’ kind of way, but as a conversation that's ongoing as things progress, it works,” Nicole Wroten-Craw, director of communications at Antioch College, told International Business Times. She said students have “embraced this policy for what it is -- good, fun communication between themselves and their sexual partner.” Louise Smith, Antioch dean of community life, told CNN the school does not have an empirical way of measuring how its affirmative consent policy has affected the number of sexual assault reports on campus. But according to the U.S. Department of Education, among the 200 member student body there have been no instances of sexual assault reported since 2006 -- the earliest year records are made available.

The University of Iowa, Gettysburg College and St. Louis University have had affirmative consent policies in place for years. And even before the latest legislation was passed, the University of California's 10 campuses agreed that consent will be defined as an "affirmative, unambiguous and conscious decision by each participant to engage in mutually agreed-upon sexual activity."

At the University of Iowa, consent is defined as “a freely and affirmatively communicated willingness to participate in particular sexual activity or behavior, expressed either by words or clear, unambiguous actions.” According to the school’s sexual misconduct coordinator Monique DiCarlo, while the policy has been helpful in educating and preventing sexual assault on campus it is just “one tool in the prevention package,” she told International Business Times. She points to other efforts the school has been using such as monthly meetings between departments and student-led efforts to curb the incidents of sexual assault on campus.

“From a practical perspective it gives students a way to think differently about sex, sexuality and respect,” DiCarlo said about the school’s affirmative consent policy. While the university does not have a way to measure the increase or decrease in sexual assault reports since the measure was implemented in 2008, the fact three reports of sexual assault were filed on the first day of the fall semester shows more progress needs to be made.

Gettysburg College, which since 2006 has implemented a policy that defines consent as “the act of willingly and verbally agreeing [for example, by stating ‘yes’] to engage in specific sexual conduct,” also has had a spike of sexual assault reports this month. At least four incidents were reported by Gettysburg College students as of Sept. 11, according to executive director of the department of public safety Bill Lafferty. The reports led students to petition for change on social media where the hashtag #NotAJoke began trending. Gettysburg College declined to comment for this article.

Every Ivy League school except Harvard University has an affirmative consent policy. While the prestigious university recently revamped its sexual assault policy in July, it failed to broaden its definition of consent. The policy did not explicitly define consent but called sexual misconduct an “unwelcome conduct of a sexual nature.”  

Dartmouth University changed its sexual assault policy in June to include affirmative consent. The school, which is currently under investigation for violating both Title IX and the Clery Act, school averaged about 15 reports of sexual assault each year among its 6,000 student population from 2008 to 2010, Rolling Stone Magazine reported in an exposé on the Ivy League school’s hazing abuses. Until June, the school’s sexual misconduct policy defined consent as “a verbal ‘no’ (or its verbal or non-verbal equivalent) indicates an unwillingness to participate in sexual activity.”

The Clery Act and Title IX are two forms of federal legislation that target sexual assault on college campuses. The former requires annual and accurate reports of all campus crimes. The latter, passed in 1972, is an anti-discrimination law that applies to the college as a whole. In 2011, Title IX began being associated with campus sexual assault when the U.S. Department of Education's Office for Civil Rights drafted a letter asking schools to take steps to end sexual violence on campus.

In 2013, the Campus Sexual Violence Elimination Act, known as the Campus SaVE Act, went into effect, amending Title IX by making institutions include domestic violence incidents in its annual crime statistics reports. In January, the White House launched a task force to improve sexual assault policies in schools and college campuses. Its guidelines describe consent as “voluntary agreement to engage in sexual activity” whereby silence or absence of resistance does not imply consent, nor can someone who is incapacitated offer consent.

In April, the White House released the names of 55 colleges and universities under federal investigation for violating Title IX. As of Aug. 8, the Department of Education’s Office for Civil Rights is facing separate lawsuits from students, which includes 76 schools, MSNBC reported. Some institutions have changed their ways. For instance, Amherst College, which is one of the 55 institutions listed, amended its sexual misconduct policy in 2013 where complaints are no longer adjudicated by classmates or faculty but by independent trained professionals. University of California-Berkeley, University of Southern California, Vanderbilt University and Dartmouth University, Princeton University and Pennsylvania State University -- schools that now have affirmative consent policies in place -- were among those listed.  

While it’s too soon to tell if the “Yes Means Yes” law will be effective in curbing the rate of sexual assaults on campus, the change in tone is seen as a step in the right direction.  

"It requires a fundamental shift in how we think about sexual assault,” Denice Labertew of the California Coalition Against Sexual Assault told CNN about “Yes Means Yes.” “It's requiring us to say women and men should be mutually agreeing and actively participating in sexual behavior."