A QUALITATIVE VARIABLE TO SAFETY STOCK PARAMETER DEFINITION APPROACH

Resumo

The material requirement planning is normally calculated according to some parameters of inventory, such as safety stock, resupply point, maximum stock, and lead-time. Those parameters come from equations based on the historical data of demand. This paper proposes the incorporation of a qualitative variable based on the key-users knowledge of the process, to improve robustness in the safety stock calculation. The focus is directed to the maintenance items because their demand are harder to predict. The result is the decreasing of the risk of stock out and a better definition of the parameters by using the qualitative variable grouped in the standard equation for calculating safety stock. A full factorial design of experiment concept has been used to perform questions to the users what generate the qualitative variable. A real case application has demonstrated a significant decrease of the stock-out risk. Otherwise, this reduction does not has increased significantly the total monetary value of that safety stock.