AS you prepare to open those college rejection letters, or worry about having to take summer school classes, fret not – being brilliant is not in the numbers.

A roundup of IQ studies from Cambridge University Press, called the “Handbook of Expertise and Expert Performance,” proves that Thomas Edison was right all along: Genius is 99 percent perspiration.

“There are international chess masters that have below-average IQs,” says Dr. K. Anders Ericsson, a professor of psychology at Florida State University in Tallahassee, who edited the handbook.

“Basically, there is no indication that people with higher IQ are able to reach the top faster. We are finding people who meet the criteria for being skilled surgeons, chess masters, athletes or magicians. Once you start looking at what makes them successful, IQ doesn’t make any difference.”

The 918-page book raises the question of whether we should eliminate the idea of determining one’s potential through IQ altogether. Instead of accepting a child into an elite school for a number they scored on a test or scouting a CIA recruit because of his IQ score, we might “speak instead of expertise, talent or even greatness,” Ericsson says.

Writes British journalist David Dobbs in New Scientist magazine: “Examine closely even the most extreme examples – Mozart, Newton, Einstein, Stravinsky – and you find more hard-won mastery than gift.

“Geniuses are made, not born.”

In one study of adult graduates of New York City’s Hunter College Elementary School, where an admission criterion was an IQ of at least 130, researchers found most had average lives, with few achieving an extreme accomplishment.

“There were no superstars, no Pulitzer Prize or MacArthur Award winners, and only one or two familiar names,” said study leader Rena Subotnik, a research psychologist with the American Psychological Association.

The three keys to success? Hard work, persistence and a solid upbringing.

The Cambridge studies show that people who have become internationally successful invariably worked with a mentor who has been at that level.

“Ability doesn’t seem to have anything to do with it,” Ericcson says. “You need to accumulate your experience. Perfect practice makes perfect. If you’re out playing tennis and you miss an overhand volley, the game will go on. The next time the identical situation happens, you’re not going to be more successful. In order to improve, you need a special training environment where a mentor will give you appropriate shots.”

The Cambridge “Handbook” also makes the claim that in order to achieve (or overachieve) genius status, one must put in five times extra work and 10 years of effort more than an amateur.

“A lot of people think highly talented people can become good at anything rapidly,” Ericsson says. “But what this study says is that nobody has been able to rise without having practiced for 10 years. In [classical] music right now, it takes more than 15-20 years before they start winning in competitions.”