Figure 3.

Concentration Index and Index of Disparity for Education-Related Inequality in Current Smoking among U.S. Women in 1965 and 1983.

Note: The Concentration Index is calculated as two times the covariance between the smoking rate of each group and its relative rank in the cumulative distribution of the population, ranked by education, divided by the population average smoking rate. The Index of Disparity is calculated as the average deviation of each group's smoking rate from the group with the lowest rate, giving each group equal weight and expressed as a percentage of the rate in the group with the lowest rate (see the appendix for formulas).

Source: Authors’ calculations of National Health Interview Survey data (National Center for Health Statistics 2009b).