The data used to calculate your experience modification is determined by your company's anniversary rating date. The inception date, or start date, of your policies determines your company's anniversary rating date. For example, if your policies always start on January 1, your anniversary rating date would be January 1. If you have switched inception dates or if you have multiple policies with varying inception dates, determining your anniversary date may be more complicated. Your insurance professional can help you find your anniversary date.
Your anniversary rating date determines the experience period and the effective date of your experience modification. In most cases, all payroll and losses developed under any policy beginning within this period will be used in determining your experience modification. The experience period begins four years and nine months prior to your anniversary rating date and terminates one year and nine months prior to the anniversary rating date. If your anniversary rating date is January 1, 2010, the experience period is April 1, 2005 to April 1, 2008.