Scottish household survey 2018: methodology and fieldwork outcomes

3 Data Collections Methods and Instruments

Summary

• The SHS social interview is carried out using Computer Aided Personal Interviewing (CAPI).
• The social questionnaire is in two parts; Household and Random Adult.
• The SHS (between 2012 and 2018) has a core and modular design which rotates and replicates across to subsequent years. A "core" set of 20 questions is included which have been designed to be asked in consistent ways with other surveys, such as age and gender.
• The Household Composition part of the questionnaire covers topics on Accommodation, Household Services, Driving and Transport, Children and Young People, Health and Disability, House Condition Survey, Household Employment, Household Income, Household Finances and Mortgages and Rent.
• The Random Adult part of the questionnaire covers topics on Adult Characteristics, Accommodation, Neighbourhoods and Communities, Education and Training, Internet, Travel and Transport, Volunteering, Local government & services, Culture & Sport, Environment, Health, Disability & Caring and Employment.
• There was a follow-up component comprising of a 'Physical Survey' of the dwelling. Such surveys are conducted by professional surveyors through a visual inspection of the dwelling.
• Before the first interviewer visit, households were sent an advance letter and leaflet outlining the purpose of the survey and the importance of participation. Interviewers post the advance letters themselves.
• The main fieldwork for the survey runs continuously throughout the year.
• Interviewers were required to make up to six calls at an address (an initial visit plus five 'call-backs').

3.1 Use of Computer Aided Personal Interviewing (CAPI)

In common with many other large-scale government surveys, the SHS social interview 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.

CAPI programming is integral to ensuring high quality data. The main parameters of the data are defined within the programme, such as; the acceptable range of responses to a question; the acceptable relationships between questions – or, the routing; and the relationships between responses given at different questions.

Between 2012 and 2018, the SHS script was scripted using Quancept. This was the software used for both the SHS and the SHCS in 2011.

3.2 Questionnaire structure

The social questionnaire is in two parts:

• Household – Information is collected about the composition and characteristics of the household from the Highest Income Householder or their spouse/partner – this allows the SHS to produce information representative of Scottish Households;
• Random Adult – Information is collected focusing on the attitudes and experiences of a randomly selected adult member of the household. This produces data which is representative of the Scottish adult population resident in private households.

For reasons of space a handful of 'household' questions are also asked of the 'random adult'. These address household events or characteristics about which any adult member of the household would be likely to know, e.g. age, gender, religion.

Figure 3.1 provides a visual representation of the core and modular design of the SHS (between 2015 and 2018) and how this rotates and replicates across to subsequent years also. This includes a "core" set of 20 questions which have been designed to be asked in consistent ways with other surveys, such as age and gender^[8]. The subsequent "modules" of questions have been designed to be flexible in terms of topic, frequency and geography. For example, questions asked of the "full" sample and asked on an "annual" basis would be able to provide local authority level on an annual basis. Similarly, questions might only be asked of "1/3" of the sample on a "biennial" basis (i.e. asked every second year). Such questions could only get national level estimates.

A simplified version of the questionnaire can be found in the publications section of the SHS website^[9]. This includes details on how questions are allocated to the different streams. The broad topic areas, however, are described in the following section.

3.2.1. Household

The household reference person, who is the Highest Income Householder (HIH) or their spouse/partner completes part 1 of the interview ('Household'). Details of all members of the household, including children, are collected during the household interview. This includes questions related to the composition and characteristics of the household, and involves capturing basic demographic information of all members of the household, such as gender, age and economic situation at this stage, as well as detailed information on dwelling characteristics as captured through the old SHCS. The topics covered in the Household section of the survey are presented in Table 3.1.

Table 3.1: Topics covered in SHS 2018 Household component

Household Composition	People living in household, basic demographics
Accommodation	Property type, Tenure & Length of tenure, Ownership of property, Previous home
Household Services	Number of bedrooms, Internet access, Food waste/recycling
Driving and Transport	Cars, Fuel spend, Bicycles
Children and Young People	Schools and travel to school, childcare costs
Health and Disability	Long-term health condition/illness
House Condition Survey	Repairs, Satisfaction with accommodation, Adaptations, Heating (including heating patterns, control, cost and suitability), Energy efficiency and Insulation
Household Employment	Employment details including status, working patterns, type of work
Household Income	Householder/Spouse paid/self-employed/other jobs, Benefits, Other sources
Household Finances	Household financial management and material deprivation
Mortgages and Rent	Mortgage and rent, Household costs including service charges and council tax
Childcare and childcare costs	Types of childcare used, amount of childcare used and costs, reasons, satisfaction with funded childcare

Subsequently a child is selected from all household members under 16 (the 'Random Child') and the household respondent is asked questions about childcare for that child. A child who is at school is also selected (the 'Random School Child') and the household respondent answers questions about the school that child attends and the journey they make to go there^[10].

3.2.2 Random Adult

Once the composition of the household has been established, one of the adults in the household is randomly selected by the computer to complete part 2 ('Random Adult') ^[11].

This covers the behavioural and attitudinal type questions, such as satisfaction with local services, and captures further demographic information on the random adult. This element also covers the 'Travel Diary' component which asks about travel behaviours on the day previous to that of the interview day. In all households with a single adult the same person completes both the household and the random adult sections. As the number of adults in the household increases, the probability of the random adult being the same as the household respondent declines^[12].

The topics covered in the Random Adult section of the survey are presented in Table 3.2.

Table 3.2: Topics covered in SHS 2018 Random Adult component

Adult Characteristics	Basic demographics, Country of birth and date of entry
Accommodation	Housing experiences
Neighbourhoods and Communities	Rating, Belonging, Crime & Police performance, Greenspace, Anti-social Behaviour, Safety, Discrimination and Harassment, Involvement with Neighbours
Education and Training	Qualifications
Internet	Use, Methods, Public sector, Non-users, Cyber crime
Travel and Transport	Licence, Driving, Electric cars, Travel to work/education, Congestion, Car sharing, Air travel, Public transport & Incidents, Journey planning, Road accidents, and Travel diary
Volunteering, Local government & services, Culture & Sport, Environment	Vounteering, Perceptions of local government, Perceptions of local services, Culture, Sport, Views on Climate change, Access to outdoors
Health, Disability & Caring	Self-assessed health, Disability, Caring responsibilities, Concessionary travel
Employment	Employment status & Government work scheme

3.2.3 Physical survey

At the end of the Household component of the survey, the HIH is asked if they would be willing to have the follow-up component 'Physical Survey' of the dwelling arranged. Such surveys are conducted by professional surveyors through a visual inspection of the dwelling. The surveyor will assess the condition, design and energy efficiency of the home, with much of their time spent surveying the outside, but they will ask to see all the rooms inside. Results from the Physical Survey are reported on separately, for the 2018 data please see the 2018 SHCS Key Findings Report^[13].

3.3 Survey fieldwork

Before the first interviewer visit, households were sent an advance letter and leaflet outlining the purpose of the survey and the importance of participation. Interviewers were given the advance letters to post themselves in order that the letter would arrive a day or two before their first call. This helped to ensure that householders were likely to be aware of the letter and leaflet when the interviewer first visited.

The main fieldwork for the survey has an on-going monthly cycle. Interviewers were required to make up to six calls at an address (an initial visit plus five 'call-backs'). In addition to the immediate reissue of contact sheets that had been wrongly completed or where the required number of call-backs had not been made, there was an on‑going programme of reissuing 'non-contacts' in a bid to maximise the response rate.

On occasion, when an interviewer arrived at a sampled address, they would find that an address comprised more than one dwelling or household. In these cases, interviewers were required to select a household/dwelling at random using a Kish grid.

The response rates for the SHS need to take account of the continuous nature of the survey. The data file for each year will contain a small proportion of interviews conducted on sample drawn the previous year. Similarly some of the addresses issued during any year will not be carried out until after the data file has been closed for analysis.

The social survey fieldwork for the 2018 sample began in January 2018, with the aim of completing re-issues and 2018 fieldwork as a whole in February 2019. The response rate target was set at 65%. The social survey fieldwork was completed in February 2019. Physical survey fieldwork usually finishes one month after social survey fieldwork.