After years of complaints from teachers, preceptors in the Expository Writing program will now be able to teach at Harvard for an additional year.

The change, announced to teachers in a letter from Dean for Undergraduate Education Lawrence Buell earlier this month, extends the limit on preceptors' terms from four to five years.

Buell's letter emphasized the need for a balance between "continuity and replenishment" in the program's scaffing.

With the extra year, preceptors will be able to further develop their work in the program, according to Nancy Sommers, director of Expos. Officials said the Faculty's standing committee on Expos, of which Sommers is a member, approved the reform earlier this fall.

"We believed that the one extra year was recognition of the important work preceptors are doing," Sommers said. "It gives the important balance that the program needed."

For the past four years, the existence of a four-year limit has been a frequent complaint of teachers and students. A Crimson investigation last fall found that the rule hurt the quality of teaching in Expos by routinely forcing talented preceptors to leave just as they were "hitting their stride" in the program.

In 1989, then-Expos director Richard C. Marius implemented the four-year limit after several veteran teachers challenged his policies. Before and for some time after Marius' decision, preceptors were told they could stay for eight years, and some teachers said they contemplated lawsuits after learning differently.

While they praised the change, both current and former preceptors said the program must do more to keep good teachers. Several teachers and administrators have said they see no need for any limit on teacher terms at all.

"In principle, the University should find a way to keep talented teachers on staff," said Len J. Rosen. "I don't know what the mechanism for that would look like, but I think it's something to be desired."

George Packer, a teacher who left the program in 1993 because of the limit, said he sees the recent change as an acknowledgement of the problems with the four-year rule.

"It's an admission that the four-year rule was a mistake, so that's a step in the right direction," said Packer, who received a CUE Guide rating of 4.93 out of 5 in his final semester at Harvard.

"But it still doesn't serve the purpose of the teaching of writing to freshmen, which is to keep good teachers and get rid of bad ones," Packer said. Instead, Expos should develop a personnel policy which would link the length of preceptors' terms to their performance, Packer said. Another former preceptor agreed that such a personnel policy would be a good idea.

"If they want what is best for the Harvard freshmen, they want to find good teachers and keep them there as long as they keep getting great results," said Myra McLarey, who currently teaches writing at the Harvard Extension School. "The limitations never made sense to me."

Asked whether there could be further changes to the limit on teacher terms, Sommers called the recent change "the final decision."

The change might be coming now because the department is more stable than it was a few years ago, one former preceptor said.

"I think they're doing it now because things have settled down," said Adam D. Schwartz, a preceptor who left the program in 1992.