Living Costs and Food Survey Frequently Asked Questions
Questions:
What are the main differences between the Expenditure and Food Survey and the Living Costs and Food Survey?
Which years are data from the LCF/EFS available?
What population is covered by the LCF/EFS?
At which level of analysis is the LCF/EFS data available?
Do I need to use weights to analyse the LCF/EFS?
What are the differences between the raw and derived databases and which should I use?
What is the lowest geographical area for which data is available?
The LCF/EFS documentation looks rather complex. How is it structured?
Are there any other LCF/EFS databases in addition to the raw and derived databases?
Can the LCF/EFS be used to monitor change over time?
How can I link data between datasets?
When I download the LCF/EFS data I obtain a large number of files. How do I find out what each of these is about?
Before I order, how do I find out what questions/variables are included?
Where can I obtain statistics and tables on the LCF/EFS?
What format is the data in?
Is there a more general FAQ?
What are the main differences between the Expenditure and Food Survey and the Living Costs and Food Survey?
The transition from the EFS to the LCF was caused by the introduction of a number of changes in the EFS questionnaire in 2008, carried out in order to bring it under the umbrella of the Integrated Household Survey (IHS). The goal was to be able to use some of the data collected during the LCF fieldwork in the IHS datasets. In most cases these did not affect the LCF data itself: the new variables added to the questionnaires are not made available in the LCF datasets but instead in the IHS. A few variables names changed, and in a small number of cases, mostly related to summary income indicators, variables were deleted. More information is available in Volume G of the Documentation for the 2008 data.
Which years are data from the LCF/EFS available?
LCF data is available from 2008 and, except for a few minor changes, also for the period 2001-2007 via the EFS. Prior to 2001, information about consumption is available in the Family Expenditure Survey and the National Food Survey.
What population is covered by the LCF/EFS?
The LCF covers the private household population aged over 16 in the UK. Since 1998/9 the survey has included some information on children aged between 7 and 15.
At which level of analysis is the LCF/EFS data available?
LCF/EFS data are available at the person level. Information in the LCF/EFS is also available at the levels of the household, the expenditure item as well as the benefit unit. However, the LCF/EFS is predominantly designed to be used as a household level survey both in its sample design and in the topics it seeks to address. Household level analysis can often be more suitable for analysing expenditure, particularly where items are shared between household members. More information on each of these levels can be found in the ESDS Introductory guide to the LCF/EFS (pages 13-14).
Do I need to use weights to analyse the LCF/EFS?
Yes, the LCF/EFS is weighted to adjust for non-response and to gross to population estimates. Weighting is necessary because the LCF/EFS has a clustered design which makes estimates produced without weights likely to be biased. There are two weights in the LCF/EFS: WEIGHTA and WEIGHTQ. WEIGHTA is an annual weight and WEIGHTQ is a quarterly weight. The quarterly weight was introduced because sample sizes vary from quarter to quarter as a result of re-issuing addresses where there had been a non-contact or refusal to a new interviewer after an interval of a few months, so that there are more interviews in the later quarters of the year than in the first quarter. Spending patterns are seasonal and quarterly grossing counteracts any bias from the uneven spread of interviews through the year. For more information on these weights, and weighting in general, see the ESDS guide to Weighting the Social Surveys.
What are the differences between the raw and derived databases and which should I use?
The raw databases contain the data as received from the survey questionnaires. The names of the raw databases begin with the prefix ‘raw’, for example, ‘rawhh’. The derived databases contain data that is adjusted in some way after it was received. These adjusted variables are clustered into datafiles with ‘DV’ in the name, for example, ‘DVHH’.
For most users the derived data files are most relevant and user friendly, particularly as much of the data that is contained in the raw datasets is also represented in the derived datasets. If the raw data is used then great care should be exercised as the structure of these files is very complex (page 14 of the ESDS Introductory guide to the LCF/EFS provides more information).
What is the lowest geographical area for which data is available?
Data is available for Government Office Regions (GORs). There are nine GORs in England. Scotland, Wales and Northern Ireland are treated as distinct GORs.
The LCF/EFS documentation looks rather complex. How is it structured?
The LCF/EFS is complex to use compared to the other ESDS Government datasets and so it is important to study the documentation carefully. All documentation is available via the doc column on the LCF/EFS catalogue page. There is some variation in the format of documentation between years; however, in general, the following guides are available in each edition:
Volume A – User guide
Volume B – Household questionnaire
Volume C – Income questionnaire
Volume D – Expenditure questionnaire
Volume E – The Raw Database
Volume F – The Derived Database
Volume G – Database Changes
Further information on the LCF/EFS documentation can be found in the ESDS Introductory guide to the LCF/EFS (see pages 6 to 8). Please note that in 2008, the documentation is different due to the necessity of explaining the changes between the LCS and the EFS.
Are there any other databases in addition to the raw and derived databases?
Yes, the food diary database contains calculated information on the nutritional values of food and drink in households. Unlike the other databases, this is presented in Microsoft Access (single file) or Tab format (multiple files).
Can the LCF/EFS be used to monitor change over time?
Yes, as a repeated cross-sectional survey the LCF/EFS can be used to monitor patterns of aggregate change. However, the survey cannot be used to assess individual changes as we do not have repeated measures for individuals. Although the EFS replaced the Family Expenditure Survey and the National Food Survey in 2001 there are issues with comparing data from the LCF/EFS with these other sources. For example, a new measure of expenditure is used in the LCF/EFS (see the ESDS guide to Analysing change over time for more details).
How can I link data between datasets?
Depending on which level of analysis you are interested in (i.e. at the person or household level), you will need to use one or several of the following variables:
- Households (case)
- Individuals (person)
- Expenditure Items (itemnum)
A step-by-step example is provided in the ESDS Introductory guide to the LCF/EFS (page 32).
When I download the LCF/EFS data I obtain a large number of files. How do I find out what each of these is about?
The documentation provides this information (see Volume A – User Guide). A summarised version of this information is provided in the ESDS Introductory guide to the LCF (pages 16-22).
Before I order, how do I find out what questions/variables are included?
Variable lists and PDF user guides (including questionnaires) are freely available via the Doc column on the LCF catalogue page. A variable search tool is also available which allows users to find out whether a specific topic or question is covered in each of the LCF/EFS surveys (or any of the other ESDS Government surveys). The variable search tool is currently under development so if you do use it you may find a few glitches.
Where can I obtain statistics and tables on the LCF/EFS?
The results of the survey are published by two departments. ONS publish the data in 'Family Spending'. DEFRA publish the results on food consumption and nutrition in Family Food.
What format is the data in?
LCF/EFS data are available in SPSS, STATA, SAS and ASCII tab-delimited formats. The food expenditure data is presented in Microsoft Access (single file) or Tab format (multiple files).
Is there a more general FAQ?
There is a generic ESDS Government FAQ for all surveys available.
