Postcodes don't indicate individuals' social class

EDITOR—In their report Danesh and colleagues said that an individual's postcode of residence could be used as a marker for his or her social class.1 This inference was based on the association between income reported in a survey and estimated household income for postcodes supplied by a commercial company. The accompanying commentary by Ben-Shlomo and Davey Smith cautioned that researchers should not attribute population characteristics to individuals—the ecological fallacy.2 These authors questioned the meaning of the association reported …