He said the change would help Expos attract a more talented group of teachers.

"It could help them to attract better people," said Schwartz, now an assistant writing professor at Wellesley College. "When Richard Marius was in charge of the program, he bemoaned the fact that after they changed the length of service from eight years to four years, it really compromised his efforts to recruit teachers. [The extra year] makes it a more attractive job."

Rosen said the change was a significant accomplishment for Sommers, who took office on July 1. "It's impressive, I think, that she has been in her position for five months and already she has effected this kind of change," Rosen said. "That bodes well for the integrity of the program."

David S. Gewanter, a head preceptor for Expos, said an extra year will permit more fine-tuning of teaching skills and allow time for preceptors to pursue their own work.

"The thought is that people in their third and fourth year are teaching very well," Gewanter said. "[The change] gives another year of this quality teaching."

Another preceptor said that the extra year will help preceptors, because teaching well takes time.

"It takes a while to learn how to teach effectively in Expos," said Gordon L. Harvey, an administrator and teacher in the program. "If you have to leave too soon, you're just getting going when you have to think about going someplace else."

Gewanter said teachers have been totally positive about the change.

"What I'm hearing is that people are really thrilled by it," Gewanter said. "People feel tremendously supported by a move like this."

The extension, however, only applies to those currently teaching in the program. Teachers who left Expos after four years because of the previous rule cannot return for another year