Some people at the National Math and Science Initiative think I don’t appreciate them, but that’s not quite right. I enjoy their engaging television ads on great teachers and international competition. Few other private groups have done as much to make high schools more rigorous. They have some of the smartest school reformers I know.

The Dallas-based nonprofit organization has spent nearly $80 million, much of it from the ExxonMobil Foundation, in nine states. The first 136 schools in its program — of teacher training, weekend study sessions and student supports — have seen the number of passing scores on Advanced Placement math, science and English tests increase 137 percent for all students and 203 percent for African American and Hispanic students in three years. It now has 462 schools, including some in southern Virginia.

My hesitation to embrace its approach has to do with the way I was raised. My parents never paid me for good grades, while students at National Math and Science Initiative schools can get $100 for every AP exam they pass.

Teachers in the program get similar bonuses for every passing AP score in their class, as well as extra pay for the long hours they devote to their classes. That’s okay. They don’t grade the exams. They are professionals being paid for their services. It is the money to the students that bothers me.

I have been writing about the initiative and an earlier Texas program that inspired it for more than a decade. When I indulge my inner moralist and fret over the bonuses, the program leaders always have the same response: It works. It appears particularly good at motivating low-income minority students, who are often the majority in the schools it serves.

Gregg Fleisher, senior vice president of the initiative, said, “What really stands out is that while we were in only 1.5 percent of the country’s schools, we accounted for 7.4 percent of the country’s increase in passing [AP] math, science and English scores” last year.

In a 2008 study of the program that is the model for the initiative, Northwestern University economist C. Kirabo Jackson found “the campuswide increases in the percentage of students in 11th and 12th grades who take AP or IB [International Baccalaureate] exams are driven primarily by increased participation among black and Hispanic students.” He found that the portion of students scoring above 1100 on the SAT or above 24 on the ACT increased 80 percent for blacks and 50 percent for Hispanics after the program took hold.

Denver Post reporter Kevin Simpson had no trouble finding AP advocates opposed to cash incentives in his recent story about the initiative’s program in Colorado. “When students are provided rigorous, relevant, exciting curricula, that’s the motivator, not money,” Tony Lewis of the Donnell-Kay Foundation in Denver told Simpson.

Kristin Klopfenstein, an economist who is executive director of the Education Innovation Institute at the University of Northern Colorado, acknowledges more students are passing AP exams under the program, but she told Simpson that she sees no proof yet that the cash incentives to students have made the difference.

One large Harvard study has cast doubt on the power of money to motivate more learning. The best book I ever read on the subject is “Punished by Rewards: The Trouble With Gold Stars, Incentive Plans, A’s, Praise and Other Bribes” by author and lecturer Alfie Kohn. That type of motivation, he told me, “actually undermines the kind we want to promote: interest in the learning itself.”

This region produces the most successful AP and IB results in the country without kids being paid. But most of our students don’t need the money. So I will continue to watch the initiative.

To read previous columns by Jay Mathews, go to washingtonpost.