A comparison of methods for measuring socio-economic status by occupation or postal area.

Seven methods of estimating socio-economic status (SES) were compared, including four based on data specific to individuals (Blishen, Pineo-Porter, British Registrar General, Hollingshead) and three based on the average characteristics of the postal code area in which people live (income alone, education alone, income and education combined). Data from the files of 151 patients undergoing in vitro fertilization were used. The four individual scales were highly correlated among themselves (Spearman's correlation coefficient between 0.6 and 0.9) but only moderately correlated with the measures based on postal code (Spearman's correlation coefficient between 0.2 and 0.3).