An information processing device acquires a reference predicted value that is a predicted value of sales figure of a prediction target period and is calculated based on an actual value of sales figure of a past period corresponding to the prediction target period regarding each of target item groups having a trend that sales figures periodically vary in a predetermined repetition cycle; acquires a value of a contextual parameter envisaged to vary in a period shorter than the repetition cycle and affect the sales figures of the target item groups; calculates a difference value between a predicted value of the sales figure of the prediction target period predicted based on the acquired value of the contextual parameter and the reference predicted value regarding each of the target item groups; and selects an item to be recommended to a user based on the difference value calculated regarding each of the target item groups.

Read more at: https://patents.google.com/patent/US20210150613A1/en?inventor=mohamed+reda+elsayed+mohamed&oq=mohamed+reda+elsayed+mohamed