Evaluating sanitary quality and classifying urban sectors according to environmental conditions

This paper describes ho iu principal components and cluster analyses were u sed to quantitatively score and rank sanitary conditions in 30 areas of Sal vador (Northeast Brazil) and to identify groups of areas with similar envir onmental quality prior to a programme to improve sanitary infrastructure. I n collecting data, street by street, a broad definition of sanitary quality was Ic:sed, encompassing lyre and quality of housing, paving, water supply , sewage disposal, drainage and household waste disposal. Ail variables use d in the principal components analysis were coded to reflect the absence of infrastructural elements that contribute to health and environmental quali ty. Summary variables generated by the analysis were used to score the sani tary quality of each of the areas, and cluster analysis identified four gro ups of areas, representing high, intermediate, poor and very poor sanitary quality. Higher rates of parasitic infection among children aged 7-14 years of age were found in areas with the worst sanitary conditions, with preval ences increasing progressively from the group with the hest sanitary qualit y to the group with the worst sanitary quality. This kind of analysis provi des a method both to appraise the needs of each community (including being able to prioritize areas most ill need and identify areas with special sani tation needs) anti to score baseline conditions that Inter allow, the impac ts of interventions to be assessed.