This paper was presented at the conference "Unequal incomes, unequal outcomes? Economic inequality and measures of well-being" as part of session 5, "Social indicators in New York City." The conference was held at the Federal Reserve Bank of New York on May 7, 1999. The authors address some of the challenges faced by economists and others who undertake to measure well-being and inequality and to identify inequality's causes and effects. Their project - the New York City Social Indicators Survey (SIS) - uses social indicators to track economic well-being and inequality. By pushing beyond the limitations of current data sources, SIS will enable the authors to collect the data necessary to define inequality in concrete terms and evaluate whether New York City is becoming more or less unequal. Significantly, it will also shed light on what effect government policies have on inequality's magnitude and consequences.