SUMMARY
Order picking—the selection of items from storage areas to fill customer orders—is the most costly activity in warehouse operations. Among the underlying factors that affect the picking operation is batching customer orders to form picking tours. We compare various heuristics for order batching. An important component of our study is comparing various metrics that approximate the relative ‘closeness’ of a pair of orders and provide a quantifiable basis for assigning order to batches. We show, empirically, that one of the proposed solution approaches outperforms the existing incumbent method