Brenda Greene remembers the day she was invited to sit in on her child's Fairfax County classroom. What she observed was "probably the most ineffective teacher I could ever imagine.

"All she was doing was having the kids read the chapter and answer the questions at the back of the book," Greene says. "The only time they could get up was to sharpen their pencils. And she marched up and down the aisles to make sure nobody got off task. Now that's a pretty lousy learning environment."

Greene, who serves on the executive board of the Fairfax County Council of P-TAs, says she complained to the principal and was "gratified to learn the situation already was being addressed."

And "when my daughter came home and complained, 'Oh, that class is boring,' I had a much better understanding of why," Greene says.

By her actions, Greene was fulfilling a parent's "second most important function," according to M. Donald Thomas, founder of the School Management Study Group, a Utah-based organization that works to promote home-school partnerships.

"First of all you have to make money to feed your kids," he says. "Second of all you have to make sure your kids get a good education."

Many parents believe they are doing just that when they attend back-to-school nights or open school days -- an opportunity to set foot in the institution that will house their children for half their waking hours almost 200 days a year.

But many distance themselves from the schools after that.

"I think they feel they've met a parental obligation," says Robert W. Peebles, who resigned in June after seven years as Alexandria superintendent of schools. "It's hard when you're actively involved in your own job and obligations to take the time that's needed."

Back-to-school night, he says, "is just an introduction. You become familiar with the school and you get to know the faces. It's important to follow up ..."

It's one thing to care, another to critically assess whether a school is working. It helps to know what to look for and how. Educators and parents offer some suggestions:

Listen to Your Children. They can tell you who are the demanding teachers, the fair teachers and the poor teachers. Children know when they are stimulated in a class and when they are bored. But beware.

" 'How was school today?' 'Boring.' That's what you're going to hear after fourth grade," says Margaret S. Marston, who served two terms as a Virginia Board of Education member and whose three children graduated from Arlington County public schools.

"Before that you're going to hear a lot of chatter: 'Johnny did this, and Sally Sue said that, and my teacher did this, and we had lunch, and we went to play and I love art.' "

The key is to listen for "the real deep struggles ... If something seems to be repetitive in nature and of a concern," adds Marston, "go in and talk to the teacher."

Ask Questions, Don't Pass Blame. A child may misinterpret what a teacher says or does. A parent might not understand why a teacher asks the class to perform a certain task in a certain way. Listen to what the teacher has to say and then, if you're still troubled, discuss your concerns. Be prepared to strike a compromise.

According to Peebles, "Parents who have skills in working with people are going to accomplish more for their children than parents who are abrasive and antagonistic."

Sit In on Your Child's Classes. As you observe, take note: Are children free to ask questions? Is every answer treated with dignity and respect? Does the teacher actively elicit responses from all of the students? Does everyone have an opportunity to participate, or do you usually hear from the same handful of students?

Is there an appropriate balance between students' self-direction and teacher-control of learning activities? Assess the amount of "time on task," which is the time students are actively engaged in learning versus the time they spend on other things, such as reacting to distractions.

Is discipline administered fairly and firmly, but in a friendly nature? Does the teacher use several teaching methods -- such as visual and verbal presentations and memorization and problem-solving activities -- to get the same point across?

Does there appear to be a structured lesson plan? Children should be able to tell you what they are learning -- "Today we're learning how to write analytically" -- and how they are learning it -- "We're learning it by writing about why we like a particular kind of music."

Evaluate the Teacher. This is a tough one, an area that school administrators struggle with constantly. "You can't judge teachers by what teachers do because learning takes place under various personalities and methodologies," says Thomas, who left the superintendency in Salt Lake City last December.

"You can't say: 'The teacher is sitting down, therefore she's not a good teacher.' The best way to judge whether a teacher is good or not is the level of learning and satisfaction exhibited by the students."

Evaluate Test Scores. "The first element of a good school is that children learn at high levels and all children learn equally well," Thomas says. "If you don't have that element, you don't have anything."

If the principal says the school is scoring in the 85th percentile, dig further. "You might find boys are scoring at the 95th percentile but girls are scoring at the 75th," Thomas says. "Or you might find kids living in the north end of town are scoring at the 90th percentile and kids in the south end of town are scoring at the 50th. That would not be a good school."

Nationally standardized tests, such as those prepared by Scholastic Research Associates, "are a guide to whether children are learning those items it has been determined children should learn in order to function well in a literate society," Thomas says.

"There are a number of pitfalls with tests," says Richard Miller, executive director of the American Association of School Administrators. "But still they're one of the best indicators we have in terms of student achievement. A parent can look at where their youngster was the previous year and then look at where they've gone during X period of time."

According to Thomas, parents should be concerned with great deviations. "If your child is scoring at the 80th percentile in math and at the 65th percentile in reading, that tells you that your child is a fairly bright child," he says. "The teacher might say, 'Well, he's good in math but not good in reading.' Hell no. It means he's good in math but the reading program for your child is lousy."

Choose Your Child's Teacher. At the end of the school year, observe the classrooms of the next grade's teachers. Decide which teacher would be best for your child and meet with the principal to request your selection. There's no guarantee you'll get your choice, but if you go in early and present your case with sound reasoning, you should succeed.

Tour the School Building. What's happening in the locker bays? In the parking lots? Behind the school building? Are the hallways under control?

Is the school clean, attractive and well-lighted? Visit the library. How many children are making use of its resources? Do teachers share and joke with each other in the hallways and lounges, or do they isolate themselves in their classrooms? Is the secretarial staff helpful, or curt?

"I would look for pride as much in the bus driver, janitor and cafeteria worker as in the principal," Marston says. "Then you know you've got a school that's clicking."

Don't be Intimidated. Educators, like other professionals, often use jargon that's hard for people outside their field to understand.

If you don't understand what it means when an educator says: "Our children are doing very well on disaggregation of data and the achievement levels are sufficient to meet the norms of other standardized tests," don't be afraid to ask for an explanation.

Be a Partner. Should you be concerned with what you find in your school evaluation, take action. Ask other parents if they agree with your observations. If so, meet with the appropriate school official as a group.

Ask to meet alone with the teacher if it has to do with your child's work or with something you observed in the classroom. Meet with the principal if it has to do with school policy or with a problem that remains unresolved after you meet with the teacher. If problems remain unresolved, meet with the superintendent or your school board representative.

But remember: Each teacher has a class, or several classes, of students. Each principal oversees a small corporation. Don't expect to barge into a classroom or the principal's office unannounced in the middle of the day and expect to walk away with results. Schedule a time convenient for all parties and be prepared to listen. Attend the meeting with notes documenting your observations and concerns, and be ready to offer suggestions to improve the situation.

"You have the right to demand for your children the best our schools and colleges can provide. Your vigilance and your refusal to be satisfied with less than the best are the imperative first step."

The words are from "A Nation at Risk," the "open letter to the American people" that spawned a nationwide education reform movement with its release in April 1983.

According to Marston, who served on the National Commission on Excellence in Education, which released the report, those words have been reprinted on many back-to-school guides. And that, she says, advances the commission's goal.

"Parents certainly should exhibit the responsibility to check in and see how the children are doing," says Marston. "They shouldn't wait for a failure ... and blame someone else." Linda Chion-Kenney is a free-lance writer based in Columbia, Md.