Think hiring a tutor will boost your child's SAT scores? You have a lot to learn.

1. "We don't have to stick to any educational standards."
News of failing schools and the increasing competitiveness of colleges have made education a big concern for parents. To the rescue, perhaps, comes the "supplemental education" business, an estimated $2 billion-and-growing industry that includes private tutors, retail tutoring centers and test-preparation centers.

While schools must now meet federally mandated standards, these criteria don't apply to supplemental education companies. "You could end up with an excellent tutor who put up a flier at the grocery store, or a crummy tutor from a national organization," says David Hollingsworth, a private tutor in New York City who trained with test-prep powerhouse Kaplan.

To get the best help possible, start with a reliable referral — say, a favorite teacher at your child's school — then focus on credentials and experience. Ask learning centers where they find tutors and if they do background checks; if tutors are certified teachers, that's a good sign. Then get references: Ask past clients if the child's grades went up, if the tutor was reliable and, most important, if the tutor and child had a good rapport. As Hollingsworth says, "You need someone who's good with kids."

2. "Our rates aren't always pinned to quality."
Costs for tutoring can vary wildly, depending on whether your child gets private or group tutoring, and whether he receives it in-home or at a center. "In general, anywhere from $35 to $65 an hour is what you're going to be paying for good tutoring," says Gene Wade, CEO of Platform Learning, a New York-based firm that develops tutoring programs for public schools. But if you're looking for specialized tutoring, including SAT test prep, or live in a big city, the costs can multiply. In Boston rates can range from $50 to $125 an hour; in New York City they can go as high as $400 an hour.

So how do you choose where to send your kid and how much to pay? Steven Shapiro, director of Pinnacle Learning Center, a Canton, Mass.-based tutoring company, believes it's a "you get what you pay for" market — up to a certain amount. "When you start getting over the $100-per-session range, I think you have to start asking what you're trying to achieve," he says. Trying to raise a C average to a B, for instance, shouldn't merit a higher rate. Meanwhile, make sure you understand the company's pricing methodology — beware of centers that require a minimum purchase up front — and cancellation policies.

3. "Our 'guarantees' are worthless."
If you're going to sink potentially thousands of dollars into tutoring for your child, you want some assurance that it will pay off academically. Some companies seem happy to oblige. North American franchisor Sylvan Learning Center, for one, guarantees that students will improve at least one full grade-level equivalent in reading or basic math skills after 36 hours of instruction or you get an additional 12 hours free. But be careful. The fine print on Sylvan's Web site, which also touts the guarantee, shows that not all centers have to participate.

Indeed, experts say that guarantees, and even vague promises, shouldn't carry too much weight. "If (a center) says their median SAT score increase is 150 points, what that means is half the kids are below that, and half are above," says Lisa Jacobson, CEO of Inspirica, a tutoring and test-prep firm in Boston and New York. "But when parents see a number or a grade, that's what they expect."

A better way to measure success is to address specific goals, like improving studying habits, says Thomas Redicks, president of the National Tutoring Association, which offers voluntary certification for tutors. Also, make sure the center keeps parents informed through regular meetings.

4. "We award scholarships-but we're not up front about it."
"Nobody says they offer financial aid or scholarships, but they do," says Inspirica's Jacobson. "If you can't afford it, you should ask anyway." Each year, she says, Inspirica tutors volunteer at a variety of schools in New York, but the company also gives a 10 percent discount for families that enroll in 40 hours of tutoring. Pinnacle also offers a 10 percent discount when 32 sessions are purchased.

Andrea Salvador, a Victoria, Minn., homemaker whose son Robert was tutored at a local Huntington Learning Center, received a discount from the center when she purchased his tutoring hours up front. While she still found the cost to be high, it dropped the per-hour fee from $54 to about $50. Huntington also offers tuition loan programs through Sallie Mae.

Not surprisingly, private tutors often offer even more room for discounts and negotiation. Jacobson says she has given discounts herself, based on clients' ability to pay, when she did private tutoring. The important thing, she says, "is to always ask. People just don't advertise it." David Hollingsworth agrees, but argues that negotiating a discount goes more smoothly when the parent "has a respect for the fact that the tutor is trying to make a living."

5. "We teach English and math, but we specialize in sales."
Take your child to any tutoring center and she'll be barraged with assessment tests to pinpoint strengths and weaknesses — usually carrying a bill of upwards of $150. NTA's Redicks believes such tests are "absolutely unnecessary" because parents can get that information from their children's school offices. Many parents, in fact, already receive results from similar state achievement tests in the mail. That's what Julie Zemanick, an Excelsior, Minn., homemaker, discovered when she took her son to a local learning center. After paying $250, she says, "I found out from his school that they do that, and I thought, gosh, if I'd known, I wouldn't have put him through that."

Learning centers say those pricey assessments are crucial to helping center directors determine how many tutoring hours a student needs. But one former Sylvan franchise director says, "The estimate is always high. It's a computerized system that typically (estimates) 100-plus hours." A Sylvan spokesperson says estimates are "based on each student's individual assessment," averaging at about 72 hours. Regardless, before you agree to have your kid tested, ask which school tests can substitute for some or all of the center's assessments.

6. "Junior needs help cramming for the SAT? Good luck."
Fall and spring are the hot seasons for college-bound kids to take the SAT and ACT aptitude tests. But don't assume you can book a tutor for help a few weeks or even a couple months beforehand. Private tutors and test-prep centers book up long before the test-taking crunch in the spring. One northern New Jersey mom discovered that the hard way when her daughter wanted to switch tutoring companies while prepping for the SAT and SAT II. When the mother mentioned that she was considering hiring another tutor, the company declined to continue working with the girl — a mere two months before the SAT II. The owner "put me in a terrible situation," the mother says, adding that she called several already booked tutors before finding an available center — which, unfortunately, charged a per-session rate $70 higher than she had paid before. A friend of hers, she says, has already reserved a tutor for when her eighth-grade son takes the SAT — in two years.

"Tutors get booked up early," Inspirica's Jacobson says, but booking two years ahead of time "is overkill." Instead, she recommends booking a test tutor the way you do a summer camp — at least three months in advance.

7. "It's cheaper to do this online."
Tutoring services are no longer touted simply for kids who are seriously struggling in school, but also for kids who just need a nudge. A growing number of clients are like 14-year-old T.J. Frier, son of Tara Goodwin Frier, who owns a PR firm in Sharon, Mass. She hired Pinnacle Learning Center to help her son raise his B-minus in Advanced Placement math. T.J.'s teachers "recommended that he drop back down to regular, but our son really wanted to stay in advanced," she says, "so we got him a tutor." Last September he started private sessions twice a week, and Frier is pleased with his progress, saying that T.J. has developed a good rapport with his tutor and his grades are steady.

Even so, NTA's Thomas Redicks says that good students like T.J. can often benefit from peer tutoring at schools, or from free or low-cost online tutoring. "There are a few good services available for occasional help if you have a question," he says. One example is Tutor.com, whose "Live Homework Help" function lets kids connect daily with an online, prescreened and trained tutor for help with everything from algebra to science. It's free at more than 600 libraries across the nation (log on to the site to find one near you), or via subscription for $100 a month for unlimited use.

8. "We can't handle learning disabilities."
Few tutoring centers are equipped to handle students with actual disabilities such as dyslexia or even mild developmental disorders, but parents may seek them out anyway, to diagnose or even "fix" problems the child is experiencing at school. While certain tutors may be adept at recognizing blocks in a child's learning process, it's not a tutor's place to diagnose a disability. If you suspect a problem exists, ask your pediatrician to refer you to a specialist.

If your child has already been diagnosed with a learning disability, look for a tutor who is a credentialed special-education teacher. "You have to ask the company if they actually have an academic tutor who's a learning specialist with degrees, and they usually don't," Jacobson says. Beyond that, says Lynda Covey, a private tutor in Redwood City, Calif., who specializes in disabilities, ask the tutor or center director how he approaches learning disabilities; she says she likes to point out examples of famous people with learning disabilities, such as Albert Einstein, to her students. "If it's handled in a negative fashion, it can be damaging and hurt their self-esteem," she says. When you ask the center for references, be sure to ask that they come from parents whose children have faced similar hurdles.

9. "We specialize in small-group sessions, but one-to-one is best."
Many supplemental education centers specialize in small-group tutoring, where two to four students work with one tutor. That's not necessarily a bad thing: A group setting can allow for independent study time, and it can be a lot cheaper. At Pinnacle Learning Center, private tutoring is $65 a session, while a "semiprivate" session with two students per tutor is $45 to $50.

But at some chain-based centers, economic factors outweigh individual attention, and your kid may not get his fair share of help — or may just waste time listening to a tutor explain things he has already mastered. "There was pressure to always keep the student-teacher ratio at a certain number — 3 to 1 or 2 to 1," says the former Sylvan center director. "We were instructed not to leave one teacher and one student together." Sylvan's vice president of education, Richard Bavaria, defends the company's approach. "Each (student) gets individual attention," he says. Plus, he adds, "a social aspect to learning can make it more compelling." By and large, however, many experts say one-to-one tutoring is more effective. "Research overwhelmingly states that one-to-one tutoring with a structured session is required for students to do better in school," Redicks says.

10. "Your kid won't always have the same tutor."
Even if your child does go the one-on-one route, it doesn't always mean personalized care. That's too bad. A good rapport can make the help seem more like fun and less like punishment.

In fact, many learning centers can't guarantee that your child will always have the same tutor. Andrea Salvador's son, Robert, received one-to-one tutoring at the learning center he attended, but over the course of seven months, "he probably had five or six different tutors," she says. Sylvan's Bavaria says that the center can't guarantee tutor continuity, and besides, with multiple tutors, kids are exposed to different teaching styles.

To increase your child's chances of success, let the center director know you want a specific tutor, and ask about how best to accommodate such scheduling. Otherwise, make sure all the tutors are familiar with your child's curriculum, and ask centers if they'll meet with your child's teacher to discuss problems and progress. "Schools are always trying new programs," says Lisa Mlinar, a vice president at Huntington Learning Center, "and tutors need to be aware of what those programs are."