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Scotland's People: results from the 2001/2002 Scottish Household Survey
Volume 8: Technical Report
3. Data collection methods and instruments
3.1 Use of Computer Aided Personal Interviewing (CAPI)
In common with many other large-scale government surveys, the SHS is carried out using Computer Aided Personal Interviewing (CAPI). This offers a number of important advantages over traditional pen-and-paper interviewing for a survey of this kind. These include the following:
- CAPI allows greater complexity in questionnaire design, since routing and 'loops' in the interview can be automated and thus effectively hidden from the interviewer. It also eliminates the need for complex selection procedures during an interview, since random selection can be built into the program.
- Overall data quality is improved because the need for a separate data entry stage is eliminated and because automatic skip-and-fill routines and range and logic checks reduce the scope for interviewer error.
- Preliminary data are available at the end of each day's fieldwork and the lack of a separate data entry stage allows faster turnaround of results more generally.
- The CAPI system generates detailed information about the timing and duration of interviews, allowing fieldwork to be monitored more closely.
Although there are now a number of competing CAPI solutions, the contractors opted for a system running In2itive software.
3.2 Questionnaire development and changes
The original SHS questionnaire was developed between August and December 1998 by the Survey Team from NFO/MORI, working in conjunction with the Technical Group for the survey from the Scottish Executive. This followed a broader consultation exercise in which interested parties from a range of policy areas, academia, voluntary organisations and other bodies were invited to propose topics or specific questions for inclusion in the survey.
The core of the SHS questionnaire is intended to remain constant, but there is also scope for the inclusion of different modules over time. In 2001 and 2002 new questions were introduced to collect information on:
- internet access and use
- the nature of disabilities
- estimates of the proportion of households experiencing homelessness
- use of public transport and walking in the local neighbourhood in the evening and to look at perceptions of safety associated with these
- frequency of using buses and trains in the past month and perceptions of bus and train services
- social contact, neighbour disputes and police / council responses.
Some questions that were asked in 1999 and 2000 were removed from the questionnaire to make space for new questions. The revisions to the questionnaire between 2000/2001 and 2001/2002 are highlighted in Appendix 2.
3.3 Fieldwork
The main fieldwork for the survey has an on-going monthly cycle. The bulk of the interviewing for each month is completed within the first two weeks, with the second two weeks being used for mopping-up and reissues. Interviewers are required to make up to four calls at an address (an initial visit plus three 'call-backs'). In addition to the immediate reissue of 'contact sheets' which have been wrongly completed or where the required number of call-backs has not been made, there is an on-going programme of reissuing 'non-contacts' in a bid to maximise the response rate. At the end of each fieldwork year a significant number of valid but 'non-contact' addresses remain 'live'.
For calculating response rates, we need to take account of the continuous nature of the survey. The data for 2001/2002 comprises 30,639 records but this includes a small number of interviews (75) conducted on sample drawn for previous years. Similarly some of the interviews recorded in the survey sample management system were conducted after the close of 2002 data (160) and were carried out in 2003. The calculations of response rates included in this document (see sub-section 4.2) therefore report the outcomes for addresses sampled for 2001/2002 regardless of when the interview was carried out.
3.4 Questionnaire structure, length and content
It was noted earlier that the questionnaire falls into two parts: the first collecting information about the composition and characteristics of the household from the highest income householder or their spouse/partner; the second focusing mainly on the attitudes and experiences of a random adult member of the household. The former is intended to generate data representative of Scottish households and the latter data representative of the Scottish adult population resident in private households. It should be noted, however, that for reasons of space a handful of 'household' questions are also asked of the 'random adult'. These address household events or characteristics which any adult member of the household would be likely to know about (e.g. recent experience of break-ins).
During the 2001/2002 fieldwork period, the average length of the 'highest income householder' interview was 18 minutes, while that of the 'random adult' interview was 26 minutes, giving an average total interview of 44 minutes.
A copy of the full questionnaire can be found in Appendix 2. The broad topic areas, however, are as follows. In the first part of the interview (with the highest income householder or spouse/partner), respondents are asked about:
- Household composition and characteristics of household members
- Type of property/accommodation
- Vehicles in household and access to public transport
- Children in the household, satisfaction with schooling and travel to school
- Employment status of the highest income householder
- Household income from employment and other sources
- Savings and household finances.
In the second part of the interview (with the 'random adult'), respondents are asked about their own:
- Housing experiences, including homelessness
- Education qualifications
- Perceptions of the local area
- Experience of crime and victimisation and fear of crime
- Travel to work or education
- Use of private and public transport
- Travel on the previous day
- Perceptions of services and local government
- Social contact and experiences of neighbourhood disputes
- Health problems and caring responsibilities
- Employment status
- Individual income from employment and other sources
A detailed summary of the contents of the questionnaire can be found at Appendix 2.
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