Statistical Deviation
Statistical deviation observed between the anticipated delivery date and the actual receipt of goods. Lead time variance measures the inconsistency of a supply chain rather than its absolute speed. It complicates inventory planning by introducing uncertainty into the reorder point calculation.
Data Collection
Monitoring this metric requires logging the timestamps of the purchase order release and the warehouse gate entry. Large values for lead time variance indicate a lack of control in the logistics or manufacturing process. Procurement teams use this data to rank vendors and adjust safety stock levels.
Process Disruption
High instability in delivery schedules forces manufacturers to hold more inventory to avoid line stoppages. When the lead time variance increases, the reliability of just-in-time production systems decreases. This leads to higher carrying costs and a greater risk of material obsolescence.
Mitigation Strategy
Suppliers reduce the fluctuation by improving their internal production scheduling and securing dedicated shipping lanes. If the lead time variance remains high, the buyer might diversify the source of supply or implement stricter penalties in the service level agreement. Verification of the variance occurs during the quarterly business review where actual performance is compared to the baseline specified in the contract.