At the most basic level, initial rate-making involves looking at the frequency and 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.