there should be an explanation of what is meant by the unit of observation, such as a ‘session’, an ‘event’ all a ‘fixed time block’. Where respondents are given more freedom in naming their activities and activities are to be coded later, it is important to give strict guidelines on what type of behaviour to include, what definitely to exclude and level of detail required. Time budget diaries without fixed time blocks should include columns for stare and finish time for activities.