Kuppuswami's classification of socio economic status is based on all of the following indices, EXCEPT:

Kuppuswamy's classification is an index for estimation of socio-economic status. The 3 variables used in this classification to assess socio economic status are education, occupation and income. House type is not considered in this classification. Ref: Parks Textbook of Preventive and Social Medicine 20th edition page 602.