DATA QUALITY ISSUES SPECIFIC TO TIME USE
The stages where error may be introduced, as listed above, also apply to diary data. There are, in addition, a number of other data quality issues which could affect the data from self-completion diaries, from specific coding problems to broader conceptual questions.
The use of a diary in which people record their activities by time of day for two specified days was a choice based on considerable research, testing and evaluation in Canada, Europe and Australia. The ABS has tested and evaluated a range of methodologies through the Time Use Pilot Survey conducted in Sydney in 1987 and smaller pilot tests for the 1992 and 1997 TUSs.
There are two possible choices with self-completion diaries: to ask people to select from a pre-coded list of activities; or to ask them to describe their activities in their own words.
The use of a pre-coded list limits the number of categories of activities, to avoid confusing respondents. This can provide useful information when the survey is intended for a particular purpose, where tables are usually presented with a relatively small number of categories. In addition, processing diaries completed from a pre-coded list is a relatively simple exercise.
Inviting people to record activities in their own words has the advantage that:
- people are able to put their own priority on the activities they select to report;
- the more detailed activities people report can provide feedback on emerging trends, e.g. recycling activities, which may be useful for later classifications; and
- there is less of a 'leading question' effect, prompting a socially desirable answer.
The open ended survey was chosen by the ABS because the greater detail collected and stored will meet the needs of a wider variety of users and allow them to aggregate items according to their own purposes.
Sample pages at the beginning of the diary demonstrated how to record the activities showing start and finish times and giving an idea of the level of detail required. There was considerable variation, however, in the descriptions provided by respondents. This variation showed in the level of detail and in the number of activities provided. One person might report 'reading,' another 'reading a newspaper'. One might give details about peeling vegetables, cutting meat and making a cake, where another might write 'getting dinner' or 'cooking', and another might just say 'housework'. The descriptions were coded at the level of detail provided by the respondent according to the relevant descriptions.
Number of episodes
The number of episodes recorded on the file ultimately depended on:
- the definition adopted for an episode; and
- the level of detail of the activity classification.
Where there is a separate code for the detail provided, a separate episode was recorded.
Cooking and washing up are separate codes in the 1992, 1997, and 2006 Activity Classification, whereas in the 1987 pilot survey they were coded to 'meal preparation and cleanup'. On the other hand, where people reported making beds, dusting and vacuuming as a sequence, all of these were coded to one activity code, and therefore, if no other changes occurred, to one episode because the activity code is the same for all these activities. The most notable suppression of detail relates to employment related activities and educational activities, where all such activities were globally coded. The activity classification is not designed to capture specific types of employment related or educational activities.
The number of episodes per day is used as one indicator of data quality. In addition, analysis of domestic work, particularly where children are present, might examine the number of episodes and the number of simultaneous activities to point to the denser and more interrupted nature of this kind of work. For both of these purposes it is essential to recognise the limitations imposed by the structural features described above.
In particular, it is not valid to compare the number of episodes of paid work with the number of episodes of any other activity. As a consequence, it is not valid to compare the number of episodes per hour carried out by someone whose major activity is paid work with the number of episodes undertaken by someone whose main activity is domestic work, unless the paid work time is excluded.
One fundamental difficulty with classifying activities is that one activity can be: several activities at once; or described at a number of levels.
An example of the first is walking, rather than driving, to the shops, and taking the dog along. This activity combines travel for shopping, exercise and pet care in one activity episode. If the respondent reported all of this in one column entry, in this kind of case the activity emphasised by the respondent would be coded as a primary activity and the others as secondary activities.
The second issue is more difficult. An activity can be named in many different ways, to reflect different aspects of time use.
The addition of a 'Who did you do this for?' ('for whom') column in the 1997 survey (and also used in the 2006 survey) provides direct information on the purpose of an activity. Activities which can be recorded as 'helping ', 'caring' or 'unpaid community services' are not always reported at the 'intent or purpose' level. In fact they consist of, and are usually described in terms of, a wide range of specific acts; visiting, cooking, nursing, lending books, washing clothes, moving furniture, organising fundraising and so on. The existence of the 'for whom' column allows the coding of the nature of the activity rather than the purpose.
Where the information provided was not enough to determine the nature of the activity then these episodes were classified directly to the voluntary work, helping or caring codes.
The 'quality' level of the activity did not appear as readily in the way people described their activities. 'Gardening', 'cooking' and 'clothes-making' are activities included in the sections of the classification that are aggregated as unpaid work. These activities can be perceived by the people doing them as leisure rather than work activities, or as both. The 'for whom' column in the diary can be used to identify whether the activity is a leisure activity or being done for some other purpose. Therefore, the identification of voluntary work activities has been made easier.
A positive side effect of the introduction of the 'for whom' column is that the coding of paid work activities is also more accurate. For example, if a respondent went to the bank, this would be coded to purchasing services, or if they were doing paperwork it would be coded to household management. If the respondent says that they did these activities for work, then it would be accurately coded as an employment-related activity.