At the most basic level, initial ratemaking involves looking at the frequency and severity of insured perils and the expected average payout resulting from these perils. Thereafter an insurance company will collect historical loss data, bring the loss data to present value, and compare these prior losses to the premium collected in order to assess rate adequacy. Loss ratios and expense loads are also used. Rating for different risk characteristics involves at the most basic level comparing the losses with "loss relativities"—a policy with twice as many losses would therefore be charged twice as much. More complex multivariate analyses are sometimes used when multiple characteristics are involved and a univariate analysis could produce confounded results. Other statistical methods may be used in assessing the probability of future losses.
One of the best ways to get cheap car insurance is by comparing car insurance quotes — and the companies offering them. To get you started, NerdWallet looked at car insurance prices across the country for different driver profiles and coverage levels to find the cheapest rates. We’ve sliced the data in several ways to give you an idea of average costs and what factors might nudge your car insurance rate up — or even better, down.