John W. Pawasarat, an analyst and researcher who examined quantifiable data to address social problems like poverty, mass incarceration and the barriers to employment and voting faced by people of color who do not have driver’s licenses, died on Jan. 2 at a hospice in Wauwatosa, Wis., a suburb of Milwaukee. He was 70.

His wife, Lois Quinn, said the cause was prostate cancer.

Mr. Pawasarat (pronounced pah-WAH-sah-raht) found in 2005 that in Wisconsin, only 53 percent of black adults and 52 percent of Hispanic adults had driver’s licenses, compared with 85 percent of white adults.

The finding underpinned a May 2014 decision by a federal judge that Wisconsin’s law requiring citizens to present photo identification — usually a driver’s license — in order to vote was unconstitutional because blacks, Hispanics and other minority group members were disproportionately unable to participate. The United States Supreme Court agreed and blocked the law from going into effect ahead of the 2014 election.

His findings were widely cited in other states, including Indiana, Michigan and Georgia, that were confronting similar voting rights issues. And it was cited by African-American members of Congress who unsuccessfully sought a federal ban on voter I.D. laws.