Countless people do it.

It's a grown-up's version of playing hooky - skipping out of work at the last minute to get a few more hours at the beach or an extra day at the park with the kids.

But that occasional "sick" (cough, cough) day you call in when you're not really ill is hurting employers and the economy.

Last year, the rate of unscheduled absences reached its highest level since 1999, costing some large employers an estimated $850,000 per year in direct payroll expenses, according to a 2006 Unscheduled Absence Survey by CCH, a provider of human resources and employment law information and services.

With the rate of absenteeism on the rise, U.S. employers are having a hard time finding effective programs that keep healthy workers on the job, according to the survey. It also concluded that companies suffer even more when the loss of productivity, morale and temporary labor costs are considered.

Taking an unplanned day off is especially common this time of year, when the warm weather coaxes employees to duck out of work to enjoy a day of fun.

Some companies, such as Smith & Nephew Endoscopy in Mansfield, are taking measures to curb the problem with good, old-fashioned civility.

The firm - which specializes in making tools for minimally invasive surgery to reconstruct joints, and also has facilities in Andover, Oklahoma City, Italy, Japan and Britain - started distributing 'courtesy notes' to its employees to inform them when they have used all their sick days.

Even though the company reports no serious problem with absenteeism, leaving a hard-copy note to any of the 335 employees at the Mansfield facility was started a year or two ago to ensure there is some consultation between employees and their bosses.

"It's important from a communication standpoint," said Joe Metzger, vice president of corporate communications.

In a Mercer/Marsh survey of more than 600 companies with 100 or more employees, more than half reported that unscheduled absences result in reduced production. One-third noted that more employees are requesting intermittent leaves, and almost 40 percent find a reduced level of customer service and sales.

Jon Bryan, a professor of management and labor relations at Bridgewater State College, says the issue might be tied to the nation's job market.

"The job market in the United States is very tight right now, 4.5 percent unemployment," he said. "Workers can feel very secure in their jobs, and they may feel free to take more time off or pursue personal time."

Employees skipping a day of work can have a minimal or catastrophic impact, he said, depending on the type of industry. The smaller a business is, the more impact it has. And, he said, white-collar workers are far less likely to face discipline from absenteeism than blue-collar workers because of the niche they occupy in the workforce, particularly during periods of low unemployment.

Nonetheless, Bryan says taking unexcused days off in any industry, is poor practice and that, in some cases, workers need to respect their jobs more.

"Employment diligence is rewarding not only to an employee and employer, but also to the nation," he said.

But some industry experts say absenteeism is under control.

"I do not think (it's a problem). Certainly, from what we've seen, the trend seems to be the opposite," said Eve Weinbaum, an associate professor of labor studies at the University of Massachusetts at Amherst.

She says when the number of unscheduled absences first started to rise, employers began to crack down on workers, "keeping closer tabs on them."

She admits, however, that many corporations consider absenteeism to be one of their biggest problems, and as a consequence workers are finding it harder to get what they want.

"Unions are having a harder and harder time to get flexibility," Weinbaum said, adding that real problem may be the system.

She says that in France, the minimum time any worker can take off of work is five weeks per year. In the United States, however, about 40 percent of workers have zero sick days.

"We need all kinds of things: We need vacation days, sick days, personal days. Workers need to know they can have some time off," Weinbaum said.

The Family and Medical Leave Act of 1993 is something that is supposed to help with that.

Under the law - signed by President Clinton soon after he took office - most employees are entitled to up to 12 work weeks of unpaid leave during any 12-month period for the following purposes:

The birth of a son or daughter, and their care.

Adoption or foster care of a child.

Care of a spouse, son, daughter, or parent who has a serious health condition.

An employee who has a serious health condition and is unable to perform his or her job.

Chronically ill employees who need regular treatment, such as dialysis or chemotherapy.

Weinbaum says, however, that the law is too limited.

Massachusetts, for example, also has the Small Necessities Leave Act, passed in 1998.

Under certain conditions, it permits employees to take up to a total of 24 hours of leave within a 12-month period to attend a child's school activity or accompany a child or elderly relative to a doctor's appointment.