Abstract: An automated store that calculates a confidence score for virtual shopping carts of shoppers, and selects carts for manual review based on these scores. Carts with low confidence scores may be more likely to contain errors, so prioritizing manual review of these carts is a cost-effective method of improving overall accuracy. A cart confidence score may be a function of factors such as confidence in the trajectory of the shopper generated by the store tracking system, confidence in the events (such as taking an item from a shelf) that affect the cart, and confidence that events are attributed to the correct shopper. Situations that make tracking, item identification, or attribution more complex may reduce confidence levels. For example, attribution confidence may be low when multiple shoppers are near an event, and item confidence may be low if the probabilistic classifier that identifies the item assigns nontrivial probabilities to multiple items.