Imagine that you have an important business meeting scheduled for March. Your annual review, your raise, your job itself all depend upon the outcome of that meeting. If you were smart, you’d start preparing right away, and relentlessly focus on it for months. The only thing that matters is the meeting.

This sounds absurd, yet this is exactly what is happening in many of our struggling schools, where all that matters is … the test.

A child’s education in many of our lowest performing schools is driven by “test prep.” Obviously, no one ever intended our children to practice for months endlessly underlining key passages in a text, or eliminating incorrect answers on multiple choice practice questions in the name of greater accountability. But give a low-performing school a choice between raising reading and math test scores or sanctions, even closing, and this unintended consequence becomes inevitable, even sensible.

Testing is not the problem. As a nation, we spend well over half a trillion dollars on K-12 primary and secondary education — more than we spend on national defense during wartime.

As a teacher, I believe taxpayers are entitled to know if their money is well-spent. But for all the attention paid to test scores, very little is paid to how those results are achieved — and what is lost in the bargain.

I’ve had fifth-graders who have missed more than one-third of the school year, do little meaningful work, but I have been forced to promote these clearly unprepared students because “they passed the test.” Even the student who gets a “2” on a 1-4 scale is said to be “approaching grade level” and eligible for promotion — without going to summer school. Social promotion, alas, is not dead.

To students, the message is clear: your entire year comes down to the test. Performance, even attendance, for the rest of the year is optional. Last year one of my students wandered into class over an hour late and fell asleep at his desk — and this was typical behavior. His pencil might as well have been a 500-pound barbell. My stern warnings that he risked repeating the grade were dismissed. “I’m not going to be left back,” he responded earnestly, “I get good grades on the test.” Smart kid.

Consider too that in most schools the teacher is the only adult in the room with his or her students while the test is administered. “Active proctoring” — circulating around the room during the exam — is demanded by administrators. Whether it’s the pressure to deliver results or the desire to see their students perform well, teachers inevitably proctor a little too actively.

Every year, fifth-graders arrive in my classroom who tested at grade level, yet cannot add or subtract without counting on their fingers. In five years, I’ve had exactly two students come to my class knowing how to divide. I never had a student — even those who supposedly tested above grade level — who could add two simple fractions.

No one should be surprised. Since we know exactly what the test will look like, the subject to be tested, the day, the hour, and the time allotted, we spend our school days — and billions of dollars — getting ready. The result is a child who can parrot back “reading strategies” but is nonplussed when you ask him to name the three branches of government, the parts of the atom, or even the city, state, and country he or she lives in.

The unpleasant truth in many struggling schools is this: If it isn’t tested, it isn’t taught. If we want children to be truly educated, we need an accountability system that cannot be gamed, designed with the law of unintended consequences factored in.

Suppose now that I know a state inspector will show up two or three times a year in my school to administer a test. I don’t know when, which grade, or what subject will be tested. I don’t know if the assessment will be oral, written, or multiple choice. I don’t even know who will have to take the test.

A randomly generated list of students are escorted to the school library to sit for an exam in third-grade science, for example. A few months later, the inspector returns, this time with a list of fifth-graders to take a reading exam. The results of these random tests can be used to judge the school’s Adequate Yearly Progress under No Child Left Behind.

We can continue giving the existing standardized tests in reading and math to every student, but the results of those exams should be used by teachers and administrators to guide instruction for individual students, rather than an all-or-nothing roll of the dice.

With random testing, the pressure to turn class time into test prep would disappear. If high stakes tests are administered unpredictably, the only way for a school to assure a good outcome would be to educate every student to a high standard.

High-stakes testing has not been a complete bust. It has proven that even large, well-entrenched bureaucracies can respond quickly to external pressure. Let’s use that pressure to force the system to do what we as a nation want done: provide every child with a rich, meaningful, and well-rounded education.

Mr. Pondiscio taught fifth grade in the South Bronx at P.S. 277 for five years.