STANDARDIZED CLASS INTERVALS AND RATE COMPUTATION IN STATISTICAL MAPS OF MORTALITY

The standard deviation of a set of mortality or morbidity rates for areal units can be used to establish class intervals for mapping. Use of standard, rather than arbitrarily selected, mapping categories will reduce bias and error in map interpretation. The method of rate calculation employed will affect variation among rate values as well as the nature of the frequency distribution. Crude and age-adjusted rates are chosen to suit the purpose of the map, but once the choice has been made the technical characteristics of the method and its affect on variation and frequency of distribution should be considered. © 1969, Taylor & Francis Group, LLC. All rights reserved.