An example method for predicting average inventory with newly added items can include: aggregating sales data of a plurality of items, the items comprising training items and new items; identifying, using a set of predefined rules, a data set of similar items on the training items for each of the new items, the set of predefined rules comprising a first stage similarity module, a second stage similarity module, and a second stage classification module; obtaining target metrics for each of the new items, the target metrics being turn predictions from the data set of the similar items; calculating mean errors of the turn predictions to identify a set of turn predictions with mean errors lower than a dynamic threshold; obtaining an ultimate turn prediction for each new item by averaging the set of turn predictions; and predicting an average inventory for each new item based on the ultimate turn prediction.