The League of Women Voters sponsors a forum on the federal deficit, with Sens. Pete V. Domenici (R-N.M.) and Jim Sasser (D-Tenn.), and Alice Rivlin of the Brookings Institution, at 8:30 p.m. in the auditorium of the Dirksen Senate Office Building. Phone 429-1965. Recent advances and organizational challenges in materials science and engineering are the topic of a symposium, Tuesday and Wednesday at the National Academy of Sciences, 2101 Constitution Ave. NW. Phone 334-2290 to register.

Ralph Nader holds a 2 p.m. news conference at 1530 P St. NW on what he calls "phony" and "inaccurate" bills that consumers receive from utilities, repair firms and other businesses. TUESDAY

The Federal Aviation Administration holds a workshop on aviation fuel safety today through Friday at the Ramada Inn on Seminary Road in Alexandria. Phone 426-3593. The Labor Department sponsors a conference on the issues involved in increasing quality and productivity in the federal government, beginning at 9 a.m. in the auditorium of the Labor Department Building, 200 Constitution Ave. NW. Phone 523-6098.

The Office of Technology Assessment's report on the Strategic Defense Initiative is the topic of a news briefing featuring Dr. Robert Jastrow, founder of NASA's Goddard Institute for Space Studies, and Dr. Frederick Seitz, president emeritus of Rockefeller University, 11 a.m. at the Heritage Foundation, 214 Massachusetts Ave. NE.

The Institute for International Economics sponsors a press conference on further correction of the yen-dollar exchange rate, at 10:30 a.m., 11 Dupont Circle. WEDNESDAY

A seminar on environmental policy in Nicaragua begins at 12:30 p.m. at the Institute for Policy Studies, 1901 Q St. NW. Phone 234-9382. British Trade Secretary Leon Brittan speaks about trade and protectionism at 9 a.m. at the National Press Club. THURSDAY

Jose Napoleon Duarte, president of El Salvador, speaks at 9 a.m. at the National Press Club.

Planned Parenthood and national medical groups hold a news conference to discuss the federal family planning program and how it has been affected by anti-abortion members of Congress, 10:30 a.m. at the Hyatt Regency Capitol Hill. Phone 387-6556 for details.

The Commerce Department reports on September economic indicators.

The U.S. International Trade Commission meets to consider certain "Cabbage Patch Kids" dolls, 701 E St. NW. Phone 523-0161 for time and additional details. FRIDAY

Bureau of Labor Statistics reports on October unemployment. The Coalition on Women's Employment and the Full Employment Action Council will hold a briefing on the unemployment situation among women, at 11 a.m. in Room 2261 of the Rayburn House Office Building. Phone 393-7415.