Table 4.
Example 4: Illustration of a Decrease in the Index of Disparity Over the Same Period in which the Rate Ratio Increases for Each Minority Group (Relative to Whites), Based on Reported Gonorrhea Rates From 1992 (Scenario G) and 1993 (Scenario H)
| Scenario G (1992) | Scenario H (1993) | ||||
|---|---|---|---|---|---|
| Racial/Ethnic Group | Population | No. Cases | Rate (per 100,000) | No. Cases | Rate (per 100,000) |
| White, non-Hispanic | 200,000,000 | 70,800 | 35.4 | 56,600 | 28.3 |
| Black, non-Hispanic | 40,000,000 | 563,240 | 1408.1 | 482,300 | 1205.8 |
| Hispanic | 55,000,000 | 52,360 | 95.2 | 49,200 | 89.5 |
| A/PI | 20,000,000 | 4,480 | 22.4 | 4,200 | 21.0 |
| AI/AN | 3,000,000 | 2,820 | 94.0 | 2,880 | 96.0 |
| Overall | 318,000,000 | 693,700 | 218.1 | 595,180 | 187.2 |
| Disparity measure | |||||
| Black-white rate ratio | 39.8 | 42.6 | |||
| Hispanic-white rate ratio | 2.7 | 3.2 | |||
| A/PI—white rate ratio | 0.6 | 0.7 | |||
| AI/AN—white rate ratio | 2.7 | 3.4 | |||
| Index of Disparity | 166.5 | 163.8 | |||
| Weighted Index of Disparity | 137.2 | 136.9 | |||
| Gini coefficient | 0.724 | 0.728 | |||
In this example, the rate ratio increases for each minority population (when using the rate in whites as the comparator) from 1992 to 1993, whereas the Index of Disparity and the Weighted Index of Disparity both indicate a decrease in disparity.
The rates in scenarios G and H correspond to reported gonorrhea rates in 1992 and 1993, respectively27 For ease of display and comparison, the populations used in all examples reflect rounded approximations of 2014 estimates. Because we did not use actual population estimates for any given year, the case numbers were adjusted manually to correspond to the reported rates for the given year, and therefore do not match the case numbers in the surveillance reports. Similarly, the overall rate was calculated from the adjusted number of cases for each subgroup, and therefore does not match the overall rate in the surveillance reports.