Forecasting Order and Ship Time for CONUS Depots

This report is concerned with the forecast of order and ship time (OST) by CONUS depots. OST is the total elapsed time from the initiation of a request for an item by the Installation Supply Activity (ISA) until the item is received and recorded on the ISA stock accounts. The supplier of the item, in most cases, is a DoD Inventory Control Point, but may also be a commercial source or one of the depot's own manufacturing shops. Four techniques for forecasting OST at CONUS depots are evalutated against two years of OST history from New Cumberland Army Depot. Each technique uses either item history, catalog history, or both. Catalog histories are constructed by grouping items according to their DoD Item Manager and their Acquisition Advice Code. Based upon the criterion of minimum root mean square forecast error, it was found that a technique which forecasts by groups of items rather than by individual item provides significant reduction to forecast error. Further improvements to this technique are possible by allowing the individual item history to modify the pure group forecast.