While I applaud The Post's continuing series on the presidential candidates, the front-page piece on Sen. Paul Simon {Nov. 23} misrepresented his voting record. In describing Sen. Simon's voting record as evaluated by the liberal Americans for Democratic Action, the writer implied that the senator had deliberately voted more conservatively in 1984, the year of his most recent election. His ADA rating that year was only 40 percent; the following year, he earned a 95 percent. The impression left is that Sen. Simon casts his votes according to the prevailing political winds. Nothing could be further from the truth.

In its tabulation of the voting rec-ords of members of Congress, ADA evaluates a member's absence as equivalent to a negative vote -- i.e., as not supporting the liberal position. In an election year, candidates spend their time courting their constituents back home and are therefore likely to have a greater number of absences. This applied to Sen. Simon in 1984, who was engaged in a tough campaign. He cast only one vote against the liberal position. Had absences not counted against him, he would have earned an admirable 95 percent that year.

One should expect that Sen. Simon (as well as his congressional colleagues seeking the Democratic nomination for president) will have unusually low scores in 1987 and 1988 because of their campaign activities. This should not be portrayed by The Post as a sign of Sen. Simon's diminished support for the concerns of consumers, women, working people and students. It would be unfair to intimate that his philosophy has been -- or will be -- affected in any way by an election. Sen. Simon should be appreciated and evaluated for the strength of his consistent leadership of our country. Careful research could have avoided leaving any impression to the contrary.

CHERYL C. KAGAN National Board Member Americans for Democratic Action Rockville