Embodiments of the present invention provide a method for grouping similar values of an attribute type and determining the best value of an attribute type for an entity in an entity resolution system. By applying attribute grouping rules to organize similar values into groups, an accurate number of distinct values for an entity may be ascertained by counting the number of resulting groups. A preferred group may be selected from the resulting groups and a “best value” may be selected from the preferred group by applying best value rules.