Mortality and Morbidity Statistics

To the Editor:— I should like to call attention to a common fallacy in the presentation of mortality and morbidity statistics, which is illustrated again by an article by Grulee, Sanford and Herron on breast and artificial feeding inThe Journal, September 8. The fallacy consists in reporting the mortality for a group under the supervision of an organization and then comparing it with the mortality of the city or state or nation as a whole. In this article, for instance, it is stated that the mortality for the group under the care of the Infant Welfare Society of Chicago was 11.1, which was less than one fourth of the infant mortality of the same region. Now the infant mortality of the same region is made up of all the deaths of infants from the very moment of birth. The mortality of the group under the supervision of the Infant