Dean Monro said yesterday that "no good evidence or body of responsible opinion" suggests that as much as 20 per cent of Harvard's students try marijuana before they leave the University.

In a letter published in the New York Times, Monro criticized the Times's use of a student estimate that "from one-fifth to one-half of the 12,500 students...at Harvard...will have tried marijuana while in Cambridge."

The estimate first appeared in a Times news story last month and reappeared in a humor column and a summary of the week's events in education.

"I can only hope that the Times will not go on repeating the student estimate to the point where it becomes accepted as a commonplace," Monro said.

He admitted that "no estimates can be accurate or reliable" but observed that 'such estimates as our deans and doctors can arrive at are all a great deal lower than the students guesses. Some adult estimates run as low as 1 per cent, 'he said.

Monro described the University as "enormously concerned that any one of our students should smoke marijuana, even if only experimentally, for we are well aware of the hazards." And in implying that "Harvard takes a light view...of marijuana," he said, the Times's education editor was "just wrong.'