Flextime allows employees to shift their work hours around a core work period in order to better accommodate their personal needs. Flextime can be useful when a significant part of the work force has restrictions on when they can work. For example, a parent may need to leave the house late in order to ensure that children have been sent to school, while others must take time out in the afternoon to care for a sick parent. Or, employees may want to arrive early and leave early in order to avoid bad commuting traffic. By allowing flextime, an employer may be able to improve employee satisfaction and reduce employee turnover. The concept works best when the type of work performed is focused on each individual worker, rather than requiring group participation.