Exposure Bases Revisited

The paper has many purposes. They are: (1) to review the definition and selection of an exposure base and to clarify the distinction between the exposure base and variables which are used in classification: (2) to review the exposure bases currently in use for manually rated risks, and to note how the manual exposure base becomes less important as the risk size increases; (3) to highlight problems in the determination of an exposure base (including temporal mismatch, interpretive mismatch, and complexity of hazard): and (4) to discuss both the current controversy regarding the use of payroll as the exposure base for workers' compensation and the recent change in the exposure bases for general liability.