The most common way to present time-use findings is be using three parameters:

    • The duration per respondent (dpr.): This is the mean of the time spent on a given activity in a given period for all the people who took part in the research (respondents).
    • The participation rate (part.): This is the percentage of respondents who did a given activity in a given time span.
    • The duration per participant (dpp.): this is the mean time that was spent on the activity in a given time span for all the respondents who participated in the activity. 

These three parameters are related and dependent on each other.
The duration per respondent is the product of the duration per participant and the participation rate (percentage expressed as a number between 0 and 1):

Duration per respondent = duration per participant x participation rate

This rule applies as long as we look at the parameters for all days apart but does not work for a constructed mean for the week or weekend days because we only have information of one weekday and one weekend day per respondent. The parameters for the means of weekdays and weekends are thus estimates taking the number of respondents per day into account for respectively Monday, Tuesday, Wednesday, Thursday and Friday for weekdays and Saturday and Sunday for weekends. Through the applied weighting procedure the difference in the relation between duration per respondent, duration per participant and participation rate is restricted to the minimum.

An example

An example could help to interpret the results: In a weekday the respondents spend about 2h44' on a the activity 'work' (=duration per respondent).

However not everyone in the population did perform paid work on the weekdays when they filled in their diary. 37,2% of the population registered work (=participation rate).

The mean working time of the respondents who were actually working on the registered days is 7h21' for the activity 'work' (=duration per participant). 

Duration per respondent = duration per participant x participation rate

2h44' = 7h21' x 37,2%