With record numbers of students signing up for a free federal tutoring program but not attending the classes, test-preparation companies are offering such incentives as tickets to sporting events, MP3 players, and $100 Visa gift cards just for showing up.

The program, known as Supplemental Educational Services, was created by the federal No Child Left Behind Act to provide tutoring to poor children at high-needs schools that have failed to accomplish “adequate yearly progress” for two consecutive years. In the past, the city Department of Education conducted the tutoring itself, but, starting this school year, private test preparation companies and community groups took over.

Well-known national tutoring companies – among them Newton Learning, Princeton Review, Education Station, Platform Learning, and the Washington Post Company’s Kaplan K12 Learning Services – could collectively earn more than $100 million by coaching the high-needs New York City students in math and reading. But there’s a hitch: The companies get paid only if students actually show up.

And they’re not showing up. Attendance is hovering between 50% and 75% of those who enroll, according to education officials – and the 66,000 students who have enrolled represent barely one-fourth of those eligible for the free extra help.

The education department hasn’t done anything on a citywide basis to try to convince the enrolled students to attend, although officials acknowledge that attendance at the tutoring programs is too low, and the tutoring is financed in full by federal funds passed through state education authorities. The city agency’s silence has left private tutoring companies to devise their own strategies.

Princeton Review, for example, offers students gift certificates in amounts linked to the percentage of tutoring sessions they attend, according to the New York City account executive for Princeton Review, Victoria Printz. Next month, Princeton Review will launch a new incentives program for older students, which will reward those who attend classes with $10 vouchers that they can either turn in right away for a little prize, or save up. Ms. Printz said the students will be able to “buy” prizes such as personal PlayStations or MP3 players if they attend regularly.

Education Station, a division of Sylvan Learning Centers, offers students inexpensive prizes, such as pens and pencils, as well as more pricey incentives, such as basketballs, Blockbuster gift cards, and CD players.

“Even if they start coming for the money reasons, they might end up coming for the right reasons,” a representative of Education Station, Bruce Klutchko, said, adding that the company also holds pep rally-style school assemblies to encourage children to attend and calls parents when children are absent.

State rules allow providers to reward students for attendance at tutoring sessions but forbid the bribing of students to sign up.

To encourage enrollment, Newton Learning hired break-dancers to perform at supplemental-services fairs this year. The firm’s executive director of supplemental educational services, Joel Rose, said both parents and children felt the break-dancers showed “that Newton Learning is not about drill and kill, it’s about giving kids a fun academic experience after school.”

Once students sign up for tutoring with Newton, the rewards are more tangible.

The company offers its students Visa gift cards worth $100 if they post perfect attendance for the entire 80-hour after-school program, which stretches over about half the school year. Children with lower rates of attendance get gift cards in smaller denominations.

“We find that that does work,” Mr. Rose said. “That does give students an additional reason to stay in the program. But we also find that that, in and of itself, will not boost attendance. The program has to be interesting and engaging for them to want to come to the program for 80 hours.”

Eugene Wade Jr., chairman and chief executive officer of Platform Learning, a New York City-based company, said Platform’s attendance exceeds the citywide average.

Last year, Platform gave students who attended 90% of their tutoring sessions two free tickets to a Yankees game and vouchers for free snacks. The company has also given out movie tickets, and smaller prizes such as stickers and nylon bags with company logos. Mr. Wade said Platform just signed a new deal with Sony to get Walkmans in bulk.

“I don’t think there’s anything wrong with giving kids prizes if they’re linked to performance,” he said. “They get kids to commit effort and to learn.”

Mr. Wade said, however, that as expensive rewards become a selling factor, the smallest tutoring groups are at the biggest disadvantage, because they can’t make deals to get desirable prizes in bulk.

All the providers of supplemental services who talked to The New York Sun said they were playing by the rules, but many said they weren’t sure their competitors were.

A source in the city Department of Education told the Sun that the agency has inquired with state officials about the marketing techniques of some of the providers but has been told each time that the questionable tactics are approved by the state Education Department, which licenses the providers.

Separately, however, the special commissioner of investigation for the New York City school district, Richard Condon, has been investigating the providers’ techniques since fall. His spokeswoman, Aquila Haynes, said a report would be released in the next few weeks.

Although many providers – big and small – are rewarding pupils with cash prizes and electronic gizmos, not all are. The providers that said they reward students for attendance and participation didn’t report significantly higher attendance than those that didn’t.

The After-School Corporation, for example, has had attendance of around 75% without offering any sort of giveaway or incentive program. The group’s director of communications, Kathleen Carlson, said the After-School Corporation is so successful because it forges partnerships with local organizations that already offer popular after-school programs that are established in the community. The best way to lure children to after-school tutoring programs, Ms. Carlson said, is to create programs that are “rich in exciting activities.”

Kumon North America also doesn’t offer special incentives but has average attendance. Its vice president of education and communication, Matthew Lupsha, said younger Kumon participants receive tiny prizes such as stickers, while older students receive “Kumon currency” for each assignment they complete. Once a month they can exchange the fake currency for little prizes such as Magic Markers, Frisbees, and yo-yos, or, as Mr. Lupsha put it: “nothing too ambitious.”

“We’re not doing anything different to try to boost attendance with the SES students than we are with our other students,” Mr. Lupsha said. “We feel that success is an incentive in itself and we try to motivate the students by letting them experience the confidence and the self-esteem that comes through better math and reading skills.”

Mr. Lupsha said he would hope that parents would sign their children up for the programs that could most effectively boost academic skills – not the ones that give out the best rewards. But he said: “It’s sometimes hard to excite the children about learning, especially when there are significant skill gaps and you need to go back and review.”

The chairwoman of the City Council’s Committee on Education, Eva Moskowitz, said: “I don’t think you should be paying kids to come.” But Ms. Moskowitz said she doesn’t have anything against incentives in general – especially if they convince children to “come and be there for the long haul.” She said, though, that prizes should be “appropriate,” such as free tickets to a museum or a performance.

“These are kids who are unfortunately at risk,” Ms. Moskowitz said. “The tutoring is not a luxury. It’s essential.”