Filling-in missing objects in orders

Filling-in techniques are important, since missing values frequently appear in real data. Such techniques have been established for categorical or numerical values. Though lists of ordered objects are widely used as representational forms (e.g., Web search results, best-seller lists), filling-in techniques for orders have received little attention. We therefore propose a simple but effective technique to fill-in missing objects in orders. We built this technique into our collaborative filtering system.