The Inventory module tracks and maintains supply and demand history for each item at each warehouse. By tracking usage, the system highlights usage trends, seasonal fluctuations, and other information critical to forecasting and planning replenishment. Three separate screens are used to record, modify, and inquire on item usage history:

• Initial demand history for a specified item/warehouse combination is entered on the Item Warehouse History Entry (IWHE) screen. The NCAS updates the fields on this screen monthly. The MTD field is the month-to-date usage of the item for the current month. In other words, the MTD field shows the current month’s usage for the item. At the end of each month, the value in the MTD field rolls to the field displaying the previous month’s usage, and the MTD field is reset to zero. The NCAS calculates the next month’s forecasted usage using the history that has been recorded for the previous month; this is a projected demand based upon the forecasting method selected to calculate the demand.

North Carolina state policy recommends the use of the moving average method for forecasting usage of an item. The moving average method averages the usage quantities for up to the 12 previous months. This average is then used as the forecasted usage for the next month.
 
• The Item Warehouse History Update (IWHU) screen is used to modify usage history information for an item/warehouse combination. The fields on this screen are identical to the fields on the Item Warehouse History Entry (IWHE) screen. All fields on the Item Warehouse History Update (IWHU) screen can be modified with the exception of the KEYS and MTD fields. The item number and warehouse identifier are entered in the first and second KEYS fields. As daily inventory transactions such as order shipments, order returns, direct issues, direct returns, and transfers among warehouses are completed, the NCAS updates the MTD quantity. This update occurs during the nightly offline procedure.

• To inquire about usage history for a specific item/warehouse combination, the warehouse manager can utilize the Item Warehouse History Inquiry (IWHI) screen. All fields on this screen, with the exception of the KEYS fields, are display only.