Rep. Rod D. Chandler (R-Wash.) was incorrectly identified as a Democrat yesterday.

hoping to improve the technical sophistication that informs the writing of federal laws on such issues as energy, health, the environment and genetic engineering -- held a two-day school for newly elected members of Congress last week.

Nearly all the politicians played hooky.

Only six of the 43 newly elected members showed up for even a part of the sessions. They were joined by five representatives returning for second terms.

At times only one or two lawmakers were present as some of the nation's top scientists explained the seemingly arcane fields of science and described new avenues of research that are likely to affect the legislative agenda of the mid-1980s.

There was Lewis Thomas, pioneer cancer researcher, predicting that one of the hottest new medical research areas will be the parasitic diseases that are major cripplers and killers in the tropics. The causative microbes are recognized as posing unexpectedly profound biological mysteries of the sort that attract researchers' attention. If Third World countries can be freed from these plagues, Thomas said, their prospects for economic development would be much improved.

There was Leon Lederman, head of Fermilab, the nation's largest high-energy physics laboratory, explaining the latest findings on the fundamental nature of matter. He said that if the new discoveries about quarks and their subatomic kin don't lead to revolutionary practical uses, it would be the first time in physics that advances of this significance -- though pursued as pure science -- didn't pay off.

There was Maxine Singer, a prominent molecular biologist at the National Cancer Institute, explaining the architecture of the DNA molecule and how to read the genetic code. She discussed the promise of gene therapy, which may be tried within a year to cure inherited diseases, and the peril of using similar methods to make deadlier biological weapons.

Half a dozen other scientific leaders also spoke:

* Joshua Lederberg, Nobel laureate in genetics, explained how to evaluate the risks posed by toxic substances.

* John Tukey, a statistician from Bell Labs and Princeton University, showed how different statistical methods applied to the same data can be used to distort or reveal reality.

* Robert Hirsch, former leader of the government's fusion energy research program and now with Arco Oil and Gas, said the current oil glut is only "a temporary aberration" that will give way to a resumed energy crisis. When that happens, he said, it will be reasonable once again to develop costlier methods to force vast reserves of hard-to-get oil out of the ground.

"You don't often get this kind of expertise under one roof," said Richard Stallings (D-Idaho), a former history professor and the only congressman to attend all sessions. "But then I'm an educator and I understand the value of education."

Stallings' attitude, said former representative James W. Symington (D-Mo.), who also attended, is not typical.

A congressman, he said, "is an empty vessel who enjoys being empty and really doesn't care to be filled. I'm not talking about their throats or their treasuries. It's hard enough to get members of Congress to come to their own hearings. It takes a rather special person to sit down here and gain these kinds of insights and perceptions."

The seminar, held last Wednesday and Thursday, was organized by former representative Mike McCormack (D-Wash.), who now runs a consulting firm, and George Washington University's School of Engineering and Applied Science.

The seminar was sponsored by several of the country's largest scientific societies, including the National Academy of Science, the American Association for the Advancement of Science, the American Chemical Society and the Institute for Electrical and Electronics Engineers. Several high-tech corporations also donated funds.

Other members of Congress who attended were Reps. Chester G. Atkins (D-Mass.), Helen Delich Bentley (R-Md.), William W. Cobey (R-N.C.), Rod Chandler (D-Wash.), Fred J. Eckert (R-N.Y.), Nancy Johnson (R-Conn.), John Miller (R-Wash.), Ronald G. Packer (R-Calif.), J. Roy Rowland (D-Ga.) and Lindsay Thomas (D-Ga.).