Abstract Polar motion (PM), a critical element of Earth Orientation Parameters (EOP), is essential for high‐precision applications such as deep space exploration and satellite navigation. Recent advances in prediction methods utilizing Effective Angular Momentum (EAM) data have become a key pathway for enhancing PM forecast accuracy. Focusing on two operational EAM forecast products—the 14‐day product from the Swiss Federal Institute of Technology Zurich (ETH Zurich) and the 10‐day product from the German Research Centre for Geosciences (GFZ)—this study systematically evaluates their performance differences and optimal application scenarios in PM prediction over the period from May 2023 to December 2024. Our analysis examines both the intrinsic accuracy of each product and the resulting accuracy evolution of PMX and PMY predictions. The results reveal complementary strengths: GFZ's product achieves higher accuracy in short‐term forecasts, whereas ETH's product demonstrates superior performance in medium‐to‐long‐term predictions. Specifically for PMX, ETH's product outperforms GFZ's across all 1–90 day lead times, with a maximum improvement of 13.84% and an average gain exceeding 8%; compared to concurrent International Earth Rotation and Reference Systems Service (IERS) forecasts, the improvement reaches up to 43.43%. For PMY, GFZ's product is more accurate at shorter lead times (1–13 days), while ETH's performs better beyond 14 days, notably outperforming the IERS Daily product by up to 35.45% within 31 days. This research provides a scientific basis for selecting EAM data in PM prediction, offering valuable insights for optimizing PM forecasting systems and supporting high‐precision remote sensing satellite missions.
Li et al. (2026) studied this question.