Wal-Mart tightened its employee attendance policy, drawing criticism from labor groups for such practices as marking as "incomplete" any shift that begins more than 10 minutes late.

Three incomplete shifts equals one unexcused absence. Seven unexcused absences and the associate must turn in his or her blue vest.

In the Roanoke Valley, a spot-check showed variation among attendance policies at various businesses.

Atul Patel, who operates five One Stop Markets and five other convenience stores, said he requires attendance except for emergencies such as a sick child or broken water pipe or when it's dangerous to drive. He requires a doctor's note to excuse back-to-back days missed because of sickness, a policy he might tighten to require a note for every illness-related absence.

"Customers like to see the same employees every time when they come to the business," Patel said.

U.S. employers have absenteeism on their radar screens. Unscheduled absenteeism among U.S. workers stood recently at 2.5 percent, up from 2.3 percent in 2005 and the highest level since 1999, when it was 2.7 percent, according to a survey by the Harris Interactive consulting firm, as summarized by the Associated Press.

The AP wrote: "The survey found that personal illness makes up for only 35 percent of unscheduled absences, with the rest due to family issues, personal needs, stress and an entitlement mentality."

Among other measures, Wal-Mart has tightened its foul-weather policy, excusing workers from their jobs only in extreme conditions -- a blizzard, hurricane or natural disaster, the AP said. General bad weather is no longer a basis for a clerk or stocker to stay home, the news service reported.

By contrast, Roanoke County-based Advance Auto Parts described more liberal rules for its 38,000 store-level employees, saying that if it's unsafe to travel, they shouldn't.

In the health care industry, workers sometimes must travel even under difficult conditions to get to work and are expected to do so. If bad weather is predictable, nurses may spend the night at or near the hospital.

"What if you were having a heart attack and you called 911 and they said the roads were dangerous" and weren't coming, said Nancy May, spokeswoman for Lewis-Gale Medical Center in Salem. "When you go into health care it is a way of life. ... You have patients who depend on you 24-7."

Wal-Mart's new rules are drawing fire from critics who claim they are the latest attempt by the nation's largest private employer to weed out unhealthy and costly long-term workers as it seeks to cut labor costs.

John Simley, spokesman for Wal-Mart, calls the charges by labor-backed groups "invalid" and said the changes are an enhancement of the company's prior policy.

"We are formalizing and enforcing the policy to ensure greater consistency and to minimize subjectivity," he said.

"It is designed to produce a better work environment and a better shopping environment. The result is better communication and a better shopping experience," Simley said.

Documents furnished to The Associated Press by union-backed WakeUpWalmart.com show that employees must call an 800 number to report all absences and tardiness by an hour before the scheduled start time. They also have to call their manager with the confirmation code they received when calling the hotline number. In the past, employees got permission directly from their store managers.

"After a year of adopting anti-family policy after anti-family policy, Wal-Mart adds further insult to injury by adopting a new restrictive attendance policy that treats hard-working associates like children while penalizing them if, God forbid, they face a child or friend with a medical emergency," said Chris Kofinis, a spokesman at WakeUpWalmart.com, a watchdog Internet site.