My long-time friend and source Ken Bernstein, known as teacherken to his many online fans, produced the most-read article on the Post’s Web site recently. He apologized to college professors for our high schools’ failure to prepare students “for the kind of intellectual work that you have every right to expect of them.”

Just retired from an award-winning career in Prince George’s County, Ken said students are not given “meaningful social studies instruction” before they reach high school because the federal No Child Left Behind law forces elementary and middle schools to focus on reading and math. Ken said the Advanced Placement Government exams he prepared his students for put too much emphasize on memorizing content. They gave no credit for good writing. In the piece, which first appeared in Academe, the journal of the American Association of University Professors, Ken said the legislators who created the tests failed to hear teachers’ warnings of stymied learning.

I agree that many students arrive in college ill-equipped to go deep into their studies and capture vital concepts. But that was a problem long before we started rating schools by their state exam averages. As a society, we shrink from giving children challenging lessons. We worry about over-stressed youth. So what if our teenagers average less than a hour of homework a day? We want them to enjoy life. Never mind that most of their spare time, University of Michigan studies show, is spent watching TV and other electronic devices.

Ken offered no data showing students were better prepared for college before the testing regimen came into vogue. On the contrary, there is evidence we are moving toward deeper learning with more analysis and critical thinking because of great teachers like Ken using programs that insist that students apply themselves. If they don’t, college-level exams written and graded by independent experts reveal how ill-prepared for college they are.

Programs like Advanced Placement, International Baccalaureate and the Advanced International Certificate of Education, as well as community college courses, have made high school more challenging. According to the annual AP Report to the Nation released Wednesday, 954,070 members of the class of 2012 took at least one AP exam, a 102 percent increase over 2002. Of that group, 573,472 had at least one passing score on an AP exam, an 88 percent gain in a decade.

Ken complained of the “huge amount of content to be covered” in AP, but neglected to mention that the college professors and top high school teachers who design AP curriculum and exams are changing that. Students are being given more choice of free response questions on the three-hour exams, similar to the choices IB students have on their three- to five-hour exams.

Scientists and specialists praise the changes, which give talented teachers like Ken a chance to take their students deep. If they want to explore the nature of DNA for a month, they don’t have to worry so much that their students will be forced to answer a question on evolution that got less attention.

I share Ken’s respect for college teachers, but not his view that they would have done a better job introducing students to complex concepts than he did. Until AP teachers, college faculty have no independent assessments of their teaching. I think the average AP instructor is better at teaching than the average introductory course college professor. No one knows for sure because college presidents decry any efforts to check their results.

In the latest AP report, the College Board revealed hundreds of thousands of high school students ready for AP but denied a chance to take college level courses in their best subjects. Ken said he was disappointed he could not meet his high aspirations for his classes. I am more worried about bright kids never allowed to take demanding courses from great high school teachers like Ken.