PITTSBURGH — A multiyear study shows Pittsburgh police are using force less frequently when making arrests but still using more force in arresting black suspects, although that frequency is going down, too.

The report, released Thursday by Chief Cameron McLay, recommends further study of several questions, including whether officers encounter more resistance from black suspects and are, therefore, justified in using force more frequently.

“Are these differences in the degree of resistance by the subjects and/or differences in how police respond at the earliest sign of resistance?” the report asks in a section entitled “Areas of inquiry.”

The city has been tracking the use of force by officers since it entered a consent decree in 1997 with the U.S. Department of Justice, designed to lower instances of police brutality. Federal overseers have since determined the city improved its policies and practices and their oversight ended in 2002.

Still, Pittsburgh continued to collect statistics. The latest study crunched numbers from 2010 through 2015 from reports.

The study shows police used force in about four-tenths of 1 percent of all incidents, or about 1,500 of the 360,000 calls police handle annually.