A person support apparatus, such as a bed, stretcher, cot, recliner, or the like, includes an exit detection system having a plurality of force sensors that support the weight of an occupant positioned on a support surface. The force sensors are part of an exit detection system that issues an alarm when the occupant exits, or is about to exit, the person support apparatus. The distribution of weight applied to the force sensors is used to determine if the occupant is about to exit the person support apparatus. Compensation is made to the exit detection system for changes in the weight distribution that are not caused by movement of the occupant. Such changes may be due to siderail movement, support surface pivoting, and/or movement of other components of the person support apparatus.