The data came from smart surveys, which combine the collection of data captured by the several sensors available in smart phones (e.g. accelerometer, location) with data entered by the users (e.g. activities performed).
Part of the data was collected by the participants and volunteers they recruited. Eurostat provided access to two smart surveys frameworks, one focusing on time use measurement (iLog) and another on health (BigO). The frameworks were composed of an Android App which captured the data, a remote server (to where the data was securely transmitted) and in the case of BigO some predicted variables (e.g. mode of transportation used).
Besides the data collected with the two frameworks, a dataset of the same nature on teachers' working time and work load previously collected was also provided.