The Washington Post interviewed 1,600 delegates to the 1976 Democratic National Convention by mail in May and 1,808 adults nationally at the same time by telephone in its poll of attitudes on the 1980 presidential campaign.

In characteristics such as age, sex, race, income, education, region of the country represented and others, the delegates interviewed by The Post closely match the entire 1976 delegation, indicating strongly that the views expressed by the Post's sample are close to the views of the more than 3,000 convention delegates.

Overall, setting aside the few delegates who have died since 1976 and the several hundred who could not be reached by mail at their old addresses, 65 percent of the delegates who received questionnaires responded to the poll.

As for the telephone survey, a sample of 1,808 has a theoretical margin of error of about 2.5 percent. For smaller groups within that sample, the margin of error is slightly higher.

The telephone interviews were conducted from May 3 to May 17. The mail survey began May 3 and continued slightly longer.

Assisting The Post in its national political polls is Gary R. Orren, associate professor of government at Harvard University.