Mr. Turnbull, of Princeton, N.J., joined the nonprofit testing service in 1948, soon after its founding, and became its president in 1970. He resigned in 1981, but continued as a scholar in residence.
He guided the nation's best-known developer of standardized tests through "a period when it shifted from a testing organization working primarily in the field of education to an educational organization working through the medium of measurement,'' an ETS statement said.
During Mr. Turnbull's tenure as president, the consumer advocate Ralph Nader and others questioned the validity of the tests administered by the ETS, including the Scholastic Aptitude Test for college-bound students.
Mr. Nader charged in a 1980 report that the S.A.T., as a predictor of academic performance in the first year of college, added little information to that available through students' high-school grades.
Mr. Turnbull characterized the report as "misleading'' and argued that "very little'' in it was new.
One of Mr. Turnbull's particular interests was arts education. He conceived and founded the Arts Recognition and Talent Search program that each year honors high-school seniors for outstanding achievement in the arts.
More recently, Mr. Turnbull was studying the quality of education and issues of equity and access to school, college, and employment opportunities. At the time of his death, he was a member of the U.S. Secretary of Education's task force on educational technology.
Mr. Turnbull was born in Ontario, Canada, and graduated from the University of Western Ontario.
He received a master's degree and doctorate in psychology from