Stanley Kaplan, the self-taught educator who died at 90 this week, can lay a claim to having reshaped American society. He is a large part of the reason that the majority of American schoolchildren are back behind their desks this week and not running around on beaches and baseball fields until mid-September, as was traditional until quite recently. The school year starts earlier because the main project of much public education in the US is to prepare students for big standardised tests given each spring. The more time to prepare, the better. It was Kaplan who showed that huge standardised tests could be effectively studied for.

Historically, the most important of these have been the SATs, or Scholastic Aptitude Tests. The SATs are the motor of the top half of the US social system – or so they appear to nervous 18-year-olds on the verge of getting sorted into professional and social niches through the process of college admissions. Yet long after Kaplan began helping teenagers prepare for the SATs in 1946, the view persisted that cramming was pointless. The tests were supposed to measure innate aptitude rather than anything teachable. Practically everyone except Kaplan’s students believed this, even the Federal Trade Commission. After years of Kaplan’s boasting that he could raise scores significantly, the FTC decided in the late 1970s to investigate him. The implication was that Kaplan was engaged in false advertising. But the FTC’s report, published in 1979, turned into an advertisement beyond Kaplan’s wildest dreams. The body found that Kaplan’s system raised scores by about 25 points on both mathematical and verbal tests – a decisive margin in many college admissions decisions.

Kaplan launched his tutoring service as a young man in his Brooklyn bedroom. He built it through post-examination pizza parties, at which he listened in on students’ descriptions of questions on the top-secret exams. By the time he sold it to the Washington Post in 1984 for $45m, it was a vast enterprise. It now includes an online law school and a range of programmes for all kinds of scholastic and professional examinations. In recent years its revenues have been more than $1bn. It is a larger part of the Washington Post Company than the Washington Post.

Kaplan’s insight was to figure out that there was an idiom to multiple-choice tests. Choices tend to be offered in predictable ways. For instance, if a problem about ratios has the answers (a) 2/3, (b) 4/5, (c) 6/7, (d) 3/2, the right answer is probably A or D, with one of them meant to “catch” a test-taker who has reversed the terms. His study guides are full of wisdom about the prose styles of test-composers, such as: “If guessing, a good rule of thumb is: the longest choice is often the correct one.” Kaplan insisted he was a respecter of subject matter. But figuring out the “tricks” of testing would give you a leg up, whether you had mastered the subject matter or not.

This attitude towards testing plays into everything that – educationally speaking – makes Americans feel embarrassed about themselves. On first hearing Keats’s Ode on a Grecian Urn, the usual response of a young American is not to swoon, weep or ponder whether beauty is really truth, and truth beauty. It is to ask: “Will that be on the test?” A lot of educators viewed Kaplan as the opposite of an educator, as one who taught not knowledge but a practical savvy that allowed students to do without it.

Americans are cynical enough to think they can find an “angle” to help them beat the odds on a standardised test. They are not cynical about testing itself. “Teaching to the test” was a widely voiced criticism of Kaplan more than a quarter-century ago, but his philosophy has won out. The assumption at the heart of George W. Bush’s No Child Left Behind Act of 2002 – which imposed tests on public schools nationwide – is that scores and knowledge are the same thing. Now that not just children but school systems are rewarded and punished for their performance on tests, public education has been colonised by the Kaplan philosophy. Entire school systems have hired testing companies such as Kaplan to undertake the Monty Python-esque task of teaching teachers to teach students test-taking skills.

There is something radically democratic about Kaplan’s approach. He brought power to the people. Of course educators have always tested students, and the results have had consequences. But now students probe their teachers’ assessment systems for loopholes. Whether you think this is a good thing depends, in large part, on who you think the beneficiaries of Kaplanism are. Standardised tests were supposed to open higher education to the middle class (in a US sense) by removing subjective biases that favoured elites. Kaplan saw himself as a champion of lower-middle class strivers like himself, for whom the SAT was a means to level the playing field. But Kaplan’s methods were effective because they were intensive. They therefore cost a lot of money. The better-off still had a better chance at getting into the best schools, except they were paying hundreds or thousands of dollars to test-preparation courses rather than to elite prep schools. Taking SAT prep courses ceased to be optional for those who wanted a fair shot at getting into the school of their choice.

So everyone wound up back in the same place. SAT scores still tend to track parental income fairly faithfully. Except that educational advancement now goes not so much to those who know the periodic table or can translate an English passage into Latin, but to those who have learnt to outsmart an educational bureaucracy.

The writer is a senior editor at The Weekly Standard

More columns at www.ft.com/caldwell