Automobile insurance rates are established by performing calculations for defining a single tier placement dependent upon a combination of mutually exclusive factors based on applicant data. The factors include a household driving record gradient, a stability gradient and an operator driving record gradient. In the case of a new policy, the factors also include a named insured driving experience gradient and a prior insurance gradient. Alternately, in the case of a renewal policy, the factors also include a household claims record gradient, a member relationship gradient and an operator claims record gradient. No single factor is the sole determinant for placement in a tier.