American pollster, the first to develop the scientific poll for political forecasting. Three times he predicted the reelection of President Franklin D. Roosevelt (1936, 1940, 1944).

Roper studied at the University of Minnesota and the University of Edinburgh without receiving a degree. He operated a jewelry store in Creston, Iowa, from 1922 to 1928 and then became a salesman for a succession of clock and manufacturing companies (1928–33).

In 1933 Roper joined with marketing expert Paul T. Cherington and writer Richardson Wood in a marketing research firm—Cherington, Roper and Wood—which lasted (without Wood) until 1938, when Roper went on alone as head of Roper Research Associates, Inc. Meanwhile, the publisher Henry Luce had engaged Roper's services in 1935 to do Fortune magazine surveys of public opinion, services that Roper continued for 15 years. The 1936 presidential election first brought Roper to national attention in his very close predictions of the results.

Thereafter, Roper not only conducted public-opinion research of various kinds (employing the techniques of small samples) but also wrote a syndicated newspaper column and was editor-at-large for Saturday Review magazine. He retired in 1966.