Updating indicators for scaling the socioeconomic level of families for health research.

BACKGROUND: Socioeconomic position is a community-used concept in health research. The social level is related to numerous exposures, resources, and susceptibilities that may affect health. AIM: To update and validate a tool for scaling the socioeconomic level of families for health research. PARTICIPANTS AND METHODS: A multistage stratified cluster sampling technique was used to select 900 families (one index person per family) from urban and rural areas in the Alexandria governorate using the proportional allocation method. Ten variables reflecting parental education, parental occupation, family characteristics, financial status as well as home sanitation were reduced to a single socioeconomic status (SES) index using two methods: the Sigma scoring method and factor analysis. Reliability and validity were assessed for the developed scale. Factor scores were classified into three categories (low, medium, high) using cluster analysis, and then different cut-off points for the Sigma scoring method were used and compared with the cluster solution using the κ statistic. RESULTS: Results showed that the developed scale was both reliable (Cronbach's α coefficient α=0.79) and valid [8 out of the 10 items had high loading (>0.5) for SES]. The best cut-off points for SES classification using the proposed scoring system that yielded the highest agreement with the cluster solution (κ=0.77) were less than 40%, 40 to <70%, and at 70% or more, with an overall correct classification of 84.7%. CONCLUSION AND RECOMMENDATION: The new scale proved to be valid and reliable. This scale is recommended for use for scaling the socioeconomic level of families for health research.