The key aspects of employee attendance monitoring you'll want to capture are:
Any type of work absence (i.e., vacation, sick leave, bereavement leave, family responsibility leave, etc.)
Recurring absence patterns (i.e., flags that highlight patterns such as an employee that calls in sick every Monday)
Employee start and stop times, especially for hourly workers, or for firms that charge out billable hours
Compliance requirements, such as limits to the number of consecutive hours an employee can work, or the number of consecutive days in a row an employee can work