Researchers have found that young children in lower-income families who live in high-cost areas don't do as well academically as their counterparts in low-cost areas. The study used data from a nationally representative sample of more than 17,500 children at more than 2,000 schools who started kindergarten in 1998. Differences for lower-income families according to cost of living in the area of residence held even when taking into account a comprehensive set of demographic variables.