Vance is an insurance agent and wants to get his younger accident-prone brother Nav some insurance. Because Vance is a partner at the company he is allowed to get his brother special rates and have other aspects of his brothers driving past overlooked. The insurance company tells Vance that he only has to use historical data on accident rates of drivers in his brothers age group to determine the premium his brother will have to pay. Which of the risks is Vance analyzing to determine the premium?