The police commissioner has hired the Rand Corp. to study his department’s stop-and-frisk procedures, officials announced yesterday.

In 2006, there was a more than fivefold increase in the number of situations in which police stopped, and sometimes frisked, people in New York City versus 2002, according to data released to the City Council last month.

Critics and civil rights advocates say the data point to racial profiling. Of the more than 500,000 people stopped, 55.2% were black, 30.5% were Hispanic, 11.1% were white, 2.8% were Asian, and 0.4% were listed as other.

The department argues that the high number of young black men stopped was tied to descriptions given by victims of crimes. In crime complaints, 68.5% of the suspects are described as black, a spokesman, Deputy Commissioner Paul Browne, said.

This is the second time this year the department has responded to criticism by hiring the Rand Corp. The company is also studying the department’s firearm training and firearm discharge review process for police shootings. The January contract was for $500,000; the new contract is for $120,000.

The lead analyst of the Rand study, Gregory Ridgeway, said his team has been granted access to the digital database of stop-and-frisk data as well as the actual forms police officers fill out when they complete a stop.

Each form has 28 boxes a police officer can check to describe the reasons for a stop, including “Furtive Actions” and “Fits a Relevant Description.”

“The reason for the stop is going to be very important” in the study, Mr. Ridgeway said. “Some of them are very subjective — such as furtive movements. I suppose there is some risk that those things could be used as proxies for race. That’s something we’ll be looking at.”