Richard Smith Beal, 38, a special assistant to the president for national security affairs since 1983 who had served in the Reagan administration since 1981, died Nov. 2 at Fairfax Hospital after surgery for a heart ailment. He lived in Herndon.

He was director of the White House Office of Planning and Evaluation from 1981 to 1983. He then joined the National Security Council staff where he became senior director of crisis management support and planning.

He was the author of five books and works dealing with the application of modern information systems to public policy planning. A White House spokesman said Dr. Beal was "a leader in bringing modern information technology into the highest levels of government."

During the 1980 presidential campaign, Dr. Beal worked for Richard B. Wirthlin. Wirthlin was president, and Dr. Beal the senior political analyst, of Decision Making Information (DMI), the firm that was the source of polling data for the Reagan campaign.

From their headquaters in Arlington, Dr. Beal and Wirthlin designed sophisticated computer techniques, including the Political Information System (PINS) that used polling data, Dr. Beal told Washington Post reporter David S. Broder, "not just to satisfy the information needs of the campaign, but to help the campaign decision-makers with their strategic judgments."

The system also enabled Wirthlin and Dr. Beal to "rehearse" the election many times during that campaign. On the Friday before the 1980 election day, Broder later wrote, their PINS simulation showed "the very strong probability of a big Reagan win, a probability the public polls never quite reflected."

Dr. Beal was born in Washington and reared in College Park. He earned bachelor's and master's degrees at Brigham Young University, and a doctorate in international relations from the University of Southern California in 1977.

In 1979, he was a Fulbright-Hays senior lecturer at Jawaharlal Nehru University in New Delhi. At the time he joined the Reagan White House, he was an associate professor of international relations and political science at Brigham Young University and coordinator of the university's international relations program.

Dr. Beal was a member of the Oakton Stake of the Church of Jesus Christ of Latter-day Saints.

Survivors include his wife, Ruth, and five children, Emily, Jason, Trevor, Melinda, and Quincy, all of Herndon; his mother, Virginia Beal of College Park, and two brothers, George, of Seattle, and Robert, of Farmingham, Utah.