College basketball’s men’s tournament may cost U.S. employers as much as $1.8 billion in unproductive wages during the first week of action, according to an annual survey by Chicago-based placement firm Challenger, Gray & Christmas Inc.

The figure is based on the 58.3 million people estimated to participate in office pools during the National Collegiate Athletic Association event known as “March Madness,” with each devoting 20 minutes per day to watching the games or focusing on the pools.

In a typical office pool, participants pick the winners of all 63 games, deciding which teams will win in the first five rounds and the championship game, which this year is scheduled for April 5 in Indianapolis.

“March Madness and the subsequent office pools have been going on long enough that employers can no longer claim to be caught off guard by the annual event,” John Challenger, the firm’s CEO, said in a statement. “Some have tried to squash these pools, most simply ignore them and others have found ways to embrace the tournament as a team-building and morale-boosting opportunity.”

A survey last year by Microsoft/MSN found that 45 percent of Americans planned to join at least one college basketball pool . Every 20 minutes spent ignoring work because of the tournament will cost employers $362.2 million, according to Challenger. That figure is based on the $18.70 current average hourly wage for all U.S. workers, provided by the U.S. Bureau of Labor Statistics.

The unscientific survey did not take into account that many employees who participate in office pools devote extra time to finishing their responsibilities.

Last year, Challenger’s study pegged possible employer productivity losses at $1.7 billion, and a year earlier it was $1.2 billion.