This is a tier 1 or tier 2 indicator - see Table 3.1.) At the same time, we argue it cannot stand alone as an indicator of material well-being, and that serious data and measuring issues need to be addressed before such an indicator can be relied on for an acceptable proxy. ( This is a tier 3 indicator, one that would require primary data collection, and hence cannot be measured until primary data becomes available - see Table 3.1.)