When an employee has a change in status, such as adding or subtracting dependents, or submits a new W-4 withholding form, you'll record that information and verify that the payroll system is updated. Filing is a large part of the job.
For instance, if a policy expired on January 1, 2007, the data included on the Experience modification would comprise the period from January 1, 2003 to January 1, 2006. Experience modifiers are normally recalculated for an employer annually. Each year, a newer year's data is added to the three-year window of experience used in the calculation, and the oldest year from the prior calculation is dropped off. The other two years worth of data in the rating window are also updated on an annual basis.
Many people believe the experience modifier is driven by two items-workers comp premium and the cost sustained by work related injuries. If you think this, you would be wrong. The true basis for the experience modifier calculation is payroll assigned to a particular workers comp class code and expected losses. Each employee's payroll is assigned to a workers comp class code.