Using census data to investigate the causes of the ecological fallacy.

"The authors show how data from the 2% Sample of Anonymised Records (SAR) can be combined with data from the Small Area Statistics (SAS) database to investigate the causes of the ecological fallacy in an Enumeration District (ED) level analysis. A range of census variables are examined in three ¿SAR districts'...in England. Results of comparable analyses from the 1986 Australian census are also given. The ecological fallacy arises when results from an analysis based on area-level aggregate statistics are incorrectly assumed to apply at the individual level.... A methodology is introduced which allows aggregate-level statistics to be adjusted by using individual-level information on those variables that explain much of the within-area homogeneity."