Aligning management objectives is the most challenging step in developing a collaborative demand planning process between a manufacturer and supplier. This is because it requires both parties to synchronize their strategic goals, performance metrics, and incentive structures. Achieving this alignment is crucial for ensuring that both the manufacturer and supplier work towards common goals, but it can be difficult due to differing priorities, organizational cultures, and business models. Once management objectives are aligned, it becomes easier to handle other steps such as choosing a forecast model, sharing demand histories, and agreeing to exception thresholds.