The calculation of the amounts to be made good to and paid by the several interests is a complicated matter. It involves much detail and arithmetic, and requires a full and accurate knowledge of the principles of the subject. Such adjustments are made by adjusters, who make the subject their profession. In Great Britain they are for the most part members of the Average Adjusters' Association (1870), a body which has done much careful work with a view to making and keeping the practice uniform and in accord with right principles. This association has gradually formulated, at their annual meetings, a body of practical rules which the individual members undertake to observe. For more information see: General average, and Marine Insurance.