A Hispanic police officer alleged race discrimination by a Police Department in assignments made to the "Spare List," a list of officers available to cover for other officers out for vacation, sickness, or police special events. Generally officers prefer to be on a regular beat. An expert for the plaintiff determined a statistically significant difference between Hispanic and Caucasian officers assigned to the Spare List.
How do you measure assignments to the Spare List? A number of choices can be made. Do you count the numbers of times in any given period that individual officers are assigned? The percent of their time spent on the list? Or do you address when they are on the list, and how long they stay? Selecting these measures is a critical step in determining measurements of discrimination. Simulation was used for a “permutation test” in the analysis.
A+I showed that different measures in this case resulted in sharp differences in the characterization of discrimination. In the end, in Federal District Court, the Department's use of the Spare List was not found to be discriminatory.