Scottish household survey 2018: methodology and fieldwork outcomes

1 Survey Overview

Summary

• The Scottish Household Survey (SHS) has run continuously in homes in Scotland since in 1999.
• A sample of the general population are randomly chosen to take part every year.
• From 2012 onwards, the survey was substantially redesigned to include elements of the Scottish House Condition Survey (SHCS)^[1] including the follow-up Physical Survey component.
• The new survey uses a fully unclustered core and modular structure with some questions asked of the full sample and others of a one-third sub-sample. Some questions are only asked every other year.
• While the overall sample size of the survey reduced from 2012 onwards from around 14,000 household interviews to about 10,000, the survey design improvements have meant that the precision of estimates has not been affected significantly.
• From 2012, it is possible to obtain local authority estimates on an annual basis where sample sizes produce robust estimates. Up to 2011 the data was collected over two years and the local-authority level data was available only after the two-year cycle was completed.

The Scottish Household Survey (SHS) is a continuous survey based on a sample of the general population in private residences in Scotland.

The SHS is designed to provide reliable and up-to-date information on the composition, characteristics, attitudes and behaviour of Scottish households and individuals, both nationally and at a sub-national level, and to examine the physical condition of Scotland's homes. It covers a wide range of topics. The specific aims of the survey are:

• Meet central and local Government needs for priority policy relevant data across a broad range of topics (including needs for continuing time-series of data collected by the SHS and SHCS previously);
• Be understandable and useful to stakeholders and so lead to a high level of buy-in and use of the SHS;
• Have built in flexibility to respond to different data needs regarding geography and frequency (e.g. to provide some data annually at Local Authority level, and some biennially at national level), and changes to these requirements over time;
• Align with other surveys and data vehicles (in particular the Scottish Health Survey and Scottish Crime and Justice Survey) to allow for Scottish Surveys Core Questions data to be produced;
• Produce high quality data in accordance with the Code of Practice for Official Statistics^[2] so as to provide data that is suitable for the production of National Statistics publications in a cost effective way;
• To permit disaggregation of information both geographically and in terms of population sub-groups (such as families with children or households in the social rented sector);
• To allow the relationships between social variables within households to be examined. This will support cross-analysis on a range of issues;
• To allow detailed follow-up surveys of sub-samples from the main survey sample, if required.

The survey is funded by the Scottish Government with contracts awarded for the fieldwork periods 1999 to 2002, 2003 to 2006, 2007 to 2011, 2012 to 2017 and from 2018 for 4 years with a possibility to extend the contract for a further 2 years. The survey is run through a consortium led by Ipsos MORI.

The survey started in 1999 and up to 2011 followed a fairly consistent survey design. The data was collected over two years and the local-authority level data was available only after the two-year cycle was completed. Due to the re-design of the survey, and the 2011 fieldwork being only a half of that cycle, local-authority level data is not available for 2011.

From 2012 onwards, the survey was substantially redesigned to include elements of the Scottish House Condition Survey (SHCS)^[3] including the follow-up Physical Survey component. The new SHS went in to the field with a substantially restructured sample design, integrating the previous SHCS. The new survey uses a fully unclustered core and modular structure with some questions asked of the full sample and others of a one-third sub-sample. The overall sample size has reduced from around 14,000 household interviews to about 10,000 though improvements in efficiency of the survey design mean it is possible to obtain local authority estimates on an annual basis where sample sizes produce robust estimates. This also means that any set of years can be combined to create larger samples, where necessary. While the overall sample size of the survey has reduced, the survey design improvements have meant that the precision of estimates has not been affected significantly.

1.1 Technical reports

Technical Reports have been published for each year of the survey covering the survey methodology, fieldwork outcomes and the questionnaire used. This report covers the methodology and fieldwork outcomes for the 2018 survey.

A second technical publication provides details of the survey questionnaire used in 2018. This includes a variety of information including the question and subsequently produced variable names along with any notes on handling individual questions.