Which of the following are the best approaches to use when evaluating the effectiveness of...

C offers measurable outcomes like time-to-fill, quality of hire, and turnover for before/after comparison.

D uses A/B testing logic, comparing a test group to a control group for a grounded assessment.

Extract from HRCI-aligned HR knowledge (Talent Planning and Acquisition):

SPHR-level HR must “use data analytics and benchmarking to assess staffing effectiveness.” Metrics such as pre/post KPIs and pilot program evaluations are essential for continuous improvement.