Term: Disparity Rate Difference (DRD)
Last Updated: 2010-10-20
Disparity Rate Difference (DRD) is one measure of a socioeconomic gap, subtracting the rate of the lowest neighbourhood income group from the rate of the highest neighbourhood income group (i.e., R1 minus R5 or U1 minus U5). This is sometimes referred to in the text as the "rate difference". There is also a statistical test for the time comparison of the DRD, measuring the change in the DRD or rate difference from the first to the last time period. This is given as a ratio of DRDs from the last time period to the first time period. The p-value associated with this is also provided. DRDs can be thought of as a way to express how many "more" (or "less") events occur in the lowest neighbourhood income quintile group compared to the highest.