Methods and apparatus, including computer program products, implementing and using techniques for monitoring and predicting various data related to an inventory. A data processing apparatus interacts with one or more business computers to obtain one of replenishment and consumption activity data related to an inventory. A model for variations in the inventory is created. The model is used to determine estimates of variation for one of currently planned replenishment activities and currently planned consumption activities. The estimates of variation are used to predict future inventory levels. A system including one or more agent computers is also described.