Do campus crime numbers add up? You do the math.

In college newsrooms across the country, October is circled on the calendar — or if not, it should be — as time to update the campus on the past year’s crime statistics.

Thanks to the federal Jeanne Clery Act, all colleges receiving federal aid (private as well as public) must disclose each Oct. 1 a breakdown of the preceding year’s violent and property crimes, by offense and by location. These annual Clery reports must also describe law enforcement policies and procedures, including any agreements with the city or county police force, crime-prevention programs, and more. (A thorough discussion of the information that must be disclosed appears in the SPLC’s “Covering Campus Crime” handbook, made possible by the Sigma Delta Chi Foundation.)

By themselves, these annual Clery reports can be a rich source of news. Because colleges are required to report statistics from the three most recent calendar years, journalists can easily identify recent trends and patterns. But obtaining the data is the start, not the beginning, of a reporter’s job.

Whether because of a deliberate intent to mislead the public about the extent of campus safety problems, or because of a genuine misunderstanding about what the law requires, or just because of outright carelessness, Clery statistics sometimes portray an inaccurate picture. Lately, questions have arisen about the legitimacy of crime statistics reported by West Virginia’s Marshall University, where — on a campus of 14,000 students — only two rapes show up in the last three years’ worth of Clery reports.

There is no proof that Marshall intentionally failed to count known rapes, but national figures as to the frequency of sexual assault suggest that something may be amiss — that the university is miscategorizing crimes, that some university officials responsible for coming forward and making reports — a group that includes not only campus law enforcement but also residence hall administrators, coaches, faculty advisers and campus activity directors among others — are failing to do so, or that rape victims at Marshall feel unusually uncomfortable about complaining.

This would hardly be a first. In 2007, some enterprising student journalists at Texas’ Tarleton State University realized that their university’s Clery Act figures for forcible sexual assault — zero in five years — were suspiciously low. They went back and gathered police incident reports covering that five-year period, and documented 10 rapes reported to campus police that never showed up on Tarleton’s Clery Act disclosures. As a result of that and other omissions, the U.S. Department of Education fined the college more than $130,000.

The lesson? Don’t confuse the figures with the facts — and if the figures look too good to be true, they probably are.