As of November 1, 2018, Workday is the system of record for human resources and payroll data. Historical data remains in legacy systems. Information Quest (IQ) has a Cognos HCM Year-Over-Year cube that combines legacy (historical) and Workday (current) data. The reports in *DEFINE and HRMS are still be available to retrieve historical data. A general rule of thumb is to look to Workday for data moving forward after November 2018, to legacy systems for data and history prior to Workday, and to IQ for data spanning both periods.
Note: IQ and Cognos access are restricted to authorized users. If you would like to request access refer to askUS answer How can I get access to and training for Cognos?