The numbers tell the awful story: Estimates say that 1 in 5 women on college campuses are victims of some kind of sexual assault.

And while we lament that such attacks happen so often, we applaud efforts to prevent them. The University of Minnesota developed a sex assault prevention policy and was poised to launch it this month. The proposal could subject students to disciplinary action for having sex unless both parties give what’s known as “affirmative consent.’’ But on Wednesday, after concerns were raised by members of the Board of Regents, U President Eric Kaler postponed implementation until September to allow more time for discussion.

While the intent of the policy is laudable, it won’t hurt to do a deeper evaluation of critics’ concerns. Nationally, civil liberties groups have argued that such rules are unfair in campus disciplinary cases because they put an undue burden of proof on the accused.

“Once that accusation has been made, it’s somehow up to the accused person to prove they did have consent,” Robert Shibley, executive director of the Philadelphia-based Foundation for Individual Rights in Education (FIRE) told the Star Tribune. “What that means is that they’re guilty until proven innocent.”

Historically too much of that burden of proof has been placed on victims. Yet it would be equally unfair to skew that responsibility too far in the other direction.

In theory, affirmative consent is designed to protect both parties in a sexual encounter. It flips the “no means no” to the proactive, pre-emptive “yes, and only yes, means yes” approach. Both participants must receive a verbal yes or some clear signal throughout activities leading to sex. For example, agreeing to a kiss is not a green light for other sexual activity — nor is silence. Because these kinds of choices often are made in the heat of the moment, however, it’s legitimate to question whether such policies are realistic and enforceable.

Should the U move ahead with the policy, it would join a growing national movement. Within the past two years, California and New York legislators voted to require colleges and universities statewide to have affirmative consent standards, and scores of colleges already have their own rules. More than 20 years ago, Antioch College received a lot of ridicule for being the first college to adopt the standard. But the federal government has made it clear that colleges must do more. In 2011, the Office of Civil Rights issued a letter that reminded institutions of their Title IX obligations to report sexual misconduct.

The “yes-means-yes approach’’ raises awareness and gives young men and women an additional way to protect themselves.

It also should help students better understand the signals they’re getting from their partners and avoid misinterpretation. The U should welcome the additional discussion in the interest of ensuring that the impact of the policies on accusers — and the accused — is clear.