Methods, systems, computer program products for determining the source of activity during interaction with a user interface are provided. The method comprises selecting one or more input devices from a plurality of available input devices coupled to the user interface and receiving respective measurements for the selected one or more input devices. Based on the received respective measurements, respective feature vectors for the one or more input devices are generated and then inputted to a pre-defined regression model. Then, the source of activity is determined based on a result received from the regression model.