This paper aims to analyse whether the Colombian government's classification of households into socio-economic strata accurately reflects the level of quality of life of households in Medellin. To this end, logit multilevel models and a novel graphic analysis were used. Our findings suggest that the stratification criteria currently used in Medellin should be revised. The socio-economic strata, which only considers the characteristics of the dwellings, streets and surrounding areas, explain approximately one tenth of the variability in self-reported quality of life. When other economic and non-economic factors are considered, a different strata ranking for guiding public policies than that used in Medellin was estimated. Neighbourhood safety and personal safety are key drivers of quality of life, whereas higher consumption expenditure is most effective in the most disadvantaged strata.