"Bob Weissman wants full-time employees. He is trying to set up a culture of people in the middle of things," said James Dougherty, analyst with Dean Witter Reynolds, New York.
Mr. Okun, 49, who had headed Nielsen for less than two years, never completely relocated to the U.S. from Switzerland.
Robert J. Lievense, 49, named exec VP of D&B and chairman of Nielsen Marketing Research and NCH Promotional Services, assumes some of Mr. Okun's duties. Mr. Lievense had been senior VP and chairman of Reuben H. Donnelley directory.
William G. Jacobi, 50, was named to head IMS International, which provides drugstore sales data, and Nielsen Media Research, the TV station ratings unit. Mr. Jacobi, who becomes exec VP of D&B and chairman of Nielsen Media Research, also manages D&B's Pension Services unit and others.
The changes at Nielsen are part of an ongoing overhaul that has seen the research company leave its secluded north suburban Chicago campus, turn over computer processing to a private company and heighten its attack on rivals, including Information Resources Inc.
IRI last week moved to expand its presence internationally. Randall Smith, who had been president of IRI's international operations, was named president of the Information Services group, adding the duties of overseeing IRI's sales force to his overseas responsibilities.
IRI said the changes resulted from the company's increased European presence, where it recently bought out its joint venture partner. Mr. Smith, who will remain in Chicago, also will continue to oversee IRI's Latin American business.