Abstract: A system to receive external data from one or more data sources, process the external data, determine available items of a first client, and retrieve user transactions associated with a targeted user. User attributes of the targeted user and item attributes of the available items are paired and the mean purchasing frequency for each of the pairs is determined. Global transactions of a population of users are analyzed to determine the standard deviation and a global mean purchasing frequency. A relevance score for each user attribute and item attribute pair is calculated. The item relevance score for each available item is determined based on the relevance score for each of the user attribute and item attribute pairs. Available items of the first client are selected based upon calculated relevance scores.