Abstract: Described are techniques for determining long-term effects of an experimental change to a user experience after the end of the experiment. A control state and a treatment state of a statistical hypothesis experiment may be assigned to first and second client devices, respectively, during an experiment time period. Subsequent to the end of the experiment, presentation of the control state may be discontinued. Result data corresponding to the treatment state may be determined during the experiment time period and for a length of time subsequent to the experiment time period. Result data corresponding to the control state may be determined during the experiment time period, and for a length of time prior to assignment of the control state to the first client device.

Abstract: Online retailers may provider various content to the electronic commerce website such as advertisements. Content on the electronic commerce website may be optimized by assigning attribution value to the content where the attribution values correspond to the influence the content may have on a customer's decision making. The attribution values may be calculated using one or more regression models.