I have been compiling data on college-level courses and exams at every public high school in the Washington area since 1998. It’s fun, like collecting baseball cards. Sometimes schools make progress. Sometimes they slip. Sometimes I find weird and exciting statistical jumps.

This year, the numbers from Stafford County triggered my curiosity. Three of its schools had big increases in Advanced Placement tests given last May. Those are difficult three-hour exams at the end of tough courses. Many students who would do well in them don’t take them, even though they help prepare for college. But at Colonial Forge High School, the number of AP tests jumped 25 percent. Tests at North Stafford High were up 56 percent. At Stafford High, the increase was 105 percent, from 543 to 1,113 tests. The passing rates declined slightly from the previous year, but the number of tests with passing scores was much higher.

I sought an explanation from Valerie Cottongim, the Stafford school system’s spokeswoman. She said a nonprofit organization called Virginia Advanced Studies Strategies had given those three schools a big grant to strengthen AP. That sounded familiar. After a few moments, I remembered.

Uh-oh.

Virginia Advanced Studies Strategies, funded by the nonprofit National Math and Science Initiative, are the backers of a movement I have been warning against for years. They pay bonus money to students and teachers for good AP exam scores. This is the first time this initiative has reached the Washington area.

The dollars involved are astonishing, at least to me. Every English, math or science AP test at the three Stafford schools with a passing grade from independent College Board readers meant a $100 check for the student and another for the teacher. Checks totaling $90,800 went to students and $145,370 to teachers.

“My daughter got a check for $500,” Cottongim said. One school in Prince William County, Woodbridge High, had a 29 percent jump in AP tests and similar bonuses. How far will this spread?

The initiative has already reached 560 schools in 22 states. This year, three D.C. schools will participate — Wilson High and charter schools E.L. Haynes and KIPP College Prep. The program began with seed money from Exxon­Mobil but now has many funders, including the federal government.

My Depression-bred parents would never have paid me for good grades. My wife and I felt the same way about our kids’ work. I knew some parents paid such bonuses, but it felt like bribery to me. Education author Alfie Kohn has revealed much research showing how material rewards kill intrinsic motivation. I preferred to have students focus on the thrill of learning and bettering themselves.

But the National Math and Science Initiative is not just luring kids with money. It is spending to train teachers and give students more time to learn, after school, on Saturdays and online. A study of such incentives in D.C. schools showed no significant achievement gains, but that program did not support students and teachers as the initiative does.

Northwestern University economist C. Kirabo Jackson found that in Texas, the bonuses and extra support sparked an increase in AP and IB test takers primarily among black and Hispanic students. The portion of students scoring above 1100 on the SAT or above 24 on the ACT increased 80 percent for black students and 50 percent for Hispanic students.

Stafford County accounted for 8 percent of the increase in all public school AP passing scores in Virginia and 13 percent of the gains by minority students. There is so far no sign that students who have received initiative checks have lost their desire to learn.

So no more finger-waving rants from Grandpa Jay, at least for awhile. If the National Math and Science Initiative wants to offer your children and their teachers money for hard work, I say take it, and see what happens.