It is important to establish how long it takes to have a drug delivered and receipted in the store so that the drug does not become out of stock. This period is called the delivery or lead time. Delivery time may be days, weeks or even months. Delivery time may be longer than two months because of the following reasons:

• Poor road conditions, particularly in the rainy season,
• Poor condition of delivery vehicles,
• Increased work load at the issuing store,
• Non-availability of adequate resources at the central store,
• Consumption rate of drugs.