Good police work involves significant portions of intuition and common sense, as former Washington State Patrol Chief Ronal Serpas demonstrated two years ago.

An independent, two-year study by professors at Washington State University had just concluded there was no evidence that the Patrol engaged in racial profiling. Comforting as the data may have been, Serpas wasn’t about to become complacent, not when public opinion sampling indicated a substantial perception that profiling occurred.

“It’s difficult to believe it doesn’t happen when so many people say it does,” Serpas said at the time.

This week, a new report by WSU professors came out with findings similar to those reported in 2003: There’s no evidence that race figures into the decisions troopers make about which motorists to stop. That’s the summary line, but now, as in 2003, the details reveal a more complicated situation.

Minority-group motorists might not be targeted for stops, but once pulled over, the 2003 study found, they’re more likely than whites to be searched. Especially Native Americans in the Spokane area.

That remains true. Researchers in the latest study call it “a small but noteworthy racial disparity” and say they need more information before drawing firm conclusions. In fact, the 2005 report concedes that race is one of many factors in the way motorists are handled. Black, Hispanic and Native American drivers who have been pulled over are more likely than whites to be searched, but Asian and East Indian drivers are less likely. Young drivers are more likely than old and men more so than women.

The more serious the violation for which a driver is stopped, the more likely there will be a search, regardless of race, but the disparity is greater for minority-group drivers than for whites. That, the researchers said, is “the most serious issue involving race and searches.”

The explanation may be that those racial groups commit more offenses, or it may be that officers’ decisions about conducting a search may be influenced by the driver’s race. The researchers say any conclusions they might attempt on the information they now have about search practices would be “somewhat tentative and speculative.”

No wonder V. Anne Smith, president of the Spokane chapter of the NAACP, is hesitant to rule out profiling. Law enforcement is effective in a free society only when there is substantial trust between authorities and citizens. To achieve that, leaders such as current WSP Chief John Batiste need to win over skeptics like Smith by eradicating any hint of discriminatory conduct.

The value of the latest survey is not that it tends to absolve the Patrol of profiling – although that’s encouraging news – but that it identifies areas where still more improvements are possible.