Technical terms of quality management: X
Procedure in materials management for forecasting consumption. It is used for requirements planning, storage planning and costing. Goods or articles are classified with regard to the regularity of their sales. Products that are regularly sold in constant numbers of items are called X articles. Y articles are products that are subject to stronger fluctuations in consumption (for example, seasonal goods). Z articles are products whose sales run very irregularly or even stochastically.