Abstract: A system, for facilitating the determination of property and casualty insurance rates, is accessible by users as a desktop application or across a computer network, such as via a web site on the Internet. Each user can provide ratemaking data, in any flat-file format, to a computer or computer server, view and correct data entry errors found in the policy and claims databanks, perform sensitivity analyses, review a log of the input ratemaking parameters and the output rate level information that comprise each sensitivity analysis, review the effect of modifications to the system's default ratemaking parameters, select final input ratemaking parameters, and receive as a product of the system, insurance rates and actuarial exhibits.