Family Resources Survey 2001-02
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 is the Labour Force Survey, the Expenditure and Food Survey, the Survey of English Housing and many more. 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 British 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: The cross-governmental harmonisation programme.
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 cover 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)
Harmonised secondary inputs
- social security benefits
- consumer durables
- detailed income for substantive analysis
- accommodation type of the household
- housing costs and benefits
- household motor vehicles
- length of residence
- selected job details
The following secondary inputs are not harmonised on the FRS
- carers
- general health, although the harmonised question will be used from 2003-04
An area where the FRS output categories differ from harmonisation proposals is disability. The harmonised question for dealing with the health of individuals is:
Do you have any long-standing illness, disability or infirmity? By long-standing I mean anything that has troubled you over a period of time or that is likely to affect you over a period of time?
On the FRS, this question is slightly rephrased as:
Do you have any long-standing physical or mental illness, health problem or disability? By 'long-standing' I mean anything that has troubled you over a period of time or that is likely to affect you over a period of time? Please include problems that are due to old age.
Individuals who answer 'yes' to this question are also asked if this illness or disability limits their activities in any way and if they are included on the Local Authority Register of Disabled People. In addition all adults below pension age are asked if they are restricted in the work they can do by some illness, injury or disability. Responses to all these questions are used to define sick or disabled adults for use in the household composition and economic status classifications (ILO definitions are based on those who have stated they cannot work or look for work because of sickness/disability). Table M.7: shows health status by age group using the different definitions. As can be seen, the additional query about whether activities are limited by the illness or disability does affect the classification. The final column shows also that up to state retirement age there are some individuals who consider they are restricted in the work they can do, but have not categorised themselves as disabled.
Differences due to survey design features
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.
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.
