Burns Roper had the perfect combination of skills to be a successful pollster, family members said — an interest in the opinions of others and a firm belief in reporting those views accurately.

Roper, a professional pollster whose career spanned more than 40 years, died of lung cancer Monday. He was 77. Burns attended Yale University but left before graduating to go to work for his father’s polling company.

Roper left Yale after the required classes for his intended major changed, but he harbored no hard feelings, his son Bruce Roper said.

“He’s always had a fondness for Yale,” Bruce Roper said.

Roper joined his father Elmo Roper’s firm, Elmo Roper and Associates, which had risen to national prominence in 1936 when it was one of the few companies to successfully predict Franklin Roosevelt’s presidential victory. He later served as chairman of the board of the company, then known as the Roper Organization.

“He was very interested in the feeling of the individuals and how they felt towards issues,” Bruce Roper said.

Above all else, Roper valued integrity in polling practices, believing his readers needed to be able to trust the data he gave them, Bruce Roper said. When his firm made polling errors — at both the beginning and end of his career — Roper was quick to admit his mistakes.

“He was always driving to make it as good as it could be,” Bruce Roper said. “He wanted to make sure that people could feel confident in polls and that people would admit mistakes when they made them.”

Roper’s firm was one of many companies that incorrectly predicted the winner of the 1948 presidential election, leading to infamous headline “Dewey Defeats Truman.” Burns Roper encouraged his father to admit that they had made a mistake and look for the reason why.

In 1992, a survey conducted by Roper’s company for the American Jewish Committee yielded a surprising result: 20 percent of respondents believed that the Holocaust had not happened. Roper’s investigation found that the survey question was poorly worded. His firm conducted two new surveys on the subject, with one of the surveys finding that only eight percent did not believe the event occurred and the other placing the number at just one percent.

Roper also aided the study of polling data, serving as chairman of the Roper Center for Public Opinion Research at the University of Connecticut. The Yale Roper Collection contains some materials from the Roper Center.

Political Science professor Donald Green, director of the Institute for Social and Policy Studies, said he had met Roper at a convention of public opinion researchers.

“I said, ‘When are you pollsters going to start archiving your data so we can make use of it?’ and he growled at me and said, ‘When are you academics going to shut up and do something for us for a change?'” Green said.

Green said that since then he has tried to contribute more to the pollsters, offering “practical breakthroughs that might help pollsters extract more information from the surveys they conduct.”

Outside of polling, Roper was known as an avid flier. In World War II, Roper flew 35 combat missions as a member of the Army Air Corps. During one mission all four of his plane’s engines failed over Berlin but Roper managed to return his crew to Britain safely. Flying remained an interest in Roper’s life. After retiring in 1994, Roper became involved with a group of veterans and other fliers that met every Thursday morning for breakfast.

In addition to his son Bruce, Roper is survived by his sons David and Douglas and his daughter Candace.

–The Associated Press contributed to this report.