WHEN VIRGINIA education officials released figures in April showing that 45 percent of the state's first-year teachers had failed a new system of evaluating classroom performance, the results answered one question -- about the adequacy of the teachers. But second-round evaluation results, for the teachers who flunked the first time, have raised a second question: are the evaluations tough enough?

Prior to the evaluations, which began last fall, all that new Virginia teachers had to do was pass the National Teacher's Exam, a four-part test that requires a written essay and assesses general, professional and teaching-subject knowledge. But some system of evaluating a teacher's classroom performance was clearly in order. Virginia took the right step in deciding to watch its new instructors as they taught. The teachers were observed in the classroom by three people, usually retired teachers or principals. They had to be judged effective in at least 10 of 14 skills ranging from good questioning techniques to offering clear interpretations of the subject matter. They had to do well in their evaluations before receiving a five-year teaching certificate.

The teachers get three chances to pass the evaluations and can take seminars at regional centers on the skills in which they are deficient. Some 668 teachers took the test last fall, and 305 failed. On their second try this spring, 272 of the failing teachers passed and only six failed again. Another 27 who failed the first time quit.

William Helton, Virginia's administrative director for teacher education, certification and professional development, says the initial 45 percent failure rate showed that some new teachers simply did not take the evaluations seriously. The results, released Wednesday, of a second group of new teachers who took the evaluations for the first time this spring showed a passing rate of 69 percent. That, says Mr. Helton, shows that the new teachers are taking them more seriously. But is it not possible that evaluations that 635 out of 641 teachers can pass in two attempts are simply too easy?

A good standard will weed out those who should not be in the state's classrooms, while improving the performance of those who had trouble on the evaluations but can -- with help -- still become good teachers. But evaluations will serve no purpose at all if they are easy enough for everyone to pass.