Family Resources Survey 2003-04
The need for harmonisation of concepts and definitions
There are a wide range of Government surveys of persons and households that provide sources of social and economic statistics. As well as the FRS, there are other surveys including the Labour Force Survey, the Expenditure and Food Survey and the Survey of English Housing. These surveys were designed at different times to meet different needs. There is also the Census of Population.
In order to improve comparability of statistics, harmonised concepts were developed to make the interpretation and analysis of these data easier, so that they allow users of published sources to see a more coherent picture of society and trends within it, and to help users plan surveys (e.g. at a local level) that can provide data comparable with national surveys. A list of the current harmonised questions is available at http://www.statistics.gov.uk/harmony.
Different surveys have different purposes and hence cover topics in different depth. Harmonised questions are designed to provide the recommended minimum information to allow common classifications and facilitate the analysis of data from different surveys in combination. Not all surveys will include questions on all topics or in every year, but the recommendation is that where a topic is covered, harmonised questions should be included wherever possible.
Some surveys will require further detail on topics than can be obtained from the harmonised questions alone. It will normally be the case that such surveys already ask for that detail. The harmonised questions have been designed so that these surveys can either derive the response to the harmonised questions without asking them directly or combine them with the further detail without adding to the length of interview.
Harmonisation that extends to all or nearly all major Government household surveys covers a primary set of concepts and questions, whereas concepts and questions that apply only for a selected group of surveys belong to a secondary set.
Harmonised primary inputs
- survey reference period
- geography
- demographic information, household composition and relationships
- national identity and ethnic group
- tenure
- economic status
- industry, occupation, employment status and socio-economic class
- full or part-time work (self-assessed)
- educational attainment
Harmonised secondary inputs
- benefits and tax credits
- consumer durables
- detailed income for substantive analysis
- income as a classificatory variable
- selected job details
- accommodation type of the household
- housing costs and benefits
- length of residence
- household motor vehicles
- qualifications
- crime and fear of crime
- social capital
- carers
- general health
Harmonised outputs have also been produced. The use of these outputs will be affected by the sample size of the individual survey and it is neither feasible nor desirable to produce outputs from different surveys in a completely harmonised way. The FRS uses harmonised outputs wherever possible, which should allow users to interpret data more easily.
Differences due to survey design features
The differences in the way in which data are collected, even using harmonised survey questions, are extremely important. There are a variety of factors that lead to different estimates for harmonised questions, which include:
- question wording and context effects;
- definition differences;
- non-response bias;
- geographical coverage;
- sampled population;
- mode effect;
- acceptance of proxy information;
- treatment of multi-households;
- unit of analysis;
- field practices;
- item non-response;
- time period;
- organisational effect.
More information is available in the article 'An initial look at harmonised survey data' by Amanda White and Sarah McCreith, published in the Social Survey Methodology Bulletin 43 (July 1998), Office for National Statistics. In addition, the Office for National Statistics is currently undertaking research to update these findings using data for further survey years.