When an insurance company accepts new insurances or when the premiums of earlier accepted insurances have to be changed on renewal the company has to
— search for the factors that influence the premium and
— calculate the premium according to the values of these factors.
In order to calculate the premiums the company gathers data consisting of factors eventually influencing the amount of claims. On the basis of these data the company calculates the tariff which has to fulfill the following general principles:
1. The tariff has to be as correct as possible in relation to different risk groups.
2. The structure of the tariff has to be such that the calculation of the insurance premium is quite straightforward. With this in mind the factors influencing the tariff have to be few enough and the structure of the tariff has to be the simple (e.g. linear or multiplicative) function of the factors or it should be rather easy to put them into tabular form.
These principles are partly contradictory. If the premium is correct, the structure of the tariff is not usually simple.