The British Household Panel Survey

1. The British Household Panel Survey Nick Buck Institute for Social and Economic Research University of Essex ESRC UK Longitudinal Studies Centre

2. What is a Household Panel Study? • Household panel studies involve repeated data collection about a sample of individuals • They are distinct from cohort studies and individual level panels in following all members of sample households • First wave is similar to cross-sectional household survey (e.g. General Household Survey) • In subsequent waves follow individuals as they move between different households, and interview new household members ESRC UK Longitudinal Studies Centre

3. Why use household panel surveys • Household panel especially useful where household context is important (e.g. demographics, income dynamics, employment participation, social values) • Family relationships over time • Collects information on changing household units • Typically have short intervals between surveys, allows collection of ‘continuous’ information ESRC UK Longitudinal Studies Centre

4. The development of Household Panel Studies • Household Panel Studies have become the leading survey type for cross-national longitudinal research • Began with Panel Study of Income Dynamics in USA - analysis of poverty persistence 1968 • SOEP in Germany/ SEP in Netherlands 1984 • BHPS in GB 1991 - widening agenda • ECHP 1994 - cross national comparison (also CNEF) • Understanding of transition countries (Hungary, Bosnia) • Understanding of differences within nation states: East/West Germany, Scotland, Wales, NIHPS, NHPS ESRC UK Longitudinal Studies Centre

5. British Household Panel Survey • Annual survey of members of initial sample of 5511 households interviewed in autumn 1991 • Random sample representative of population of Great Britain (south of Caledonian canal) • The sample frame was the Postal Address File; The sample was clustered and stratified, 250 primary sampling units, stratified by region, and census social indicators. • The sample is essentially equal probability (Sampling information on file PSUs and Strata are distinguished – though not identified) ESRC UK Longitudinal Studies Centre

6. BHPS Interviews • Interviews with all adults, aged 16+, in each households (40 minute interviewer administered, plus 10 minute self completion) • Household level interview (10 minutes) • From wave 4, interviews with young people aged 11-15 ESRC UK Longitudinal Studies Centre

7. Following rules • Indefinite life panel study, ‘Following rules’ maintain representation of original population and their descendants – these specify who should be eligible to be interviewed at each wave. • The Longitudinal Sample consists of: members of original households, and their natural descendants born since the start of the panel • The above are eligible for interview each wave so long as they remain in scope (i.e. in GB / UK from 1997) • Sample members are followed as they move. ESRC UK Longitudinal Studies Centre

8. Following rules (2) • Original sample only included members of private households. At subsequent waves interviews sought with members in institutional accommodation. • At each wave the interviewed sample also contains co-residents of longitudinal sample members. These will not in general be followed if they no longer live with a sample member. • The panel sample will be reduced by: • Attrition – refusal and non-contact • Members becoming ineligible - Deaths and moves out of scope ESRC UK Longitudinal Studies Centre

9. The BHPS additional samples ESRC UK Longitudinal Studies Centre

10. Scotland and Wales Extension Samples • First Wave in 1999/2000 - Wave 9 BHPS, approximately 1500 new households in each • Sample structure similar to BHPS wave one, sub-regional stratification, Highlands and Islands • Generally contain the same questions, except where early wave life histories carried instead of BHPS variable components. • Additional questions on national identity etc. • Released with main BHPS data, and to be analysed in conjunction with those data ESRC UK Longitudinal Studies Centre

11. Northern Ireland Household Panel Survey • First Wave in 2001 - Wave 11 BHPS, approximately 2000 new households • Simple random sample across the whole of Northern Ireland • Generally contain the same questions, except where early wave life histories carried instead of BHPS variable components. • Released with main BHPS data, and can be analysed in conjunction with those data ESRC UK Longitudinal Studies Centre

12. ESRC UK Longitudinal Studies Centre

13. BHPS topics • BHPS questionnaire consists of core questions repeated each year and variable components. Core questions cover the following areas: • Housing and consumption, neighbourhood characteristics • Household organisation, domestic work • Education and training • Labour market behaviour, current job, and annual job history • Health, limitation of activities, use of health services • Social and political values, social participation and networks • Income: current and annual measures, non-monetary indicators ESRC UK Longitudinal Studies Centre

14. Questionnaire changes across time • In general questions remain fixed across the panel waves, and associated variables containing responses will be found in each waves data set. Exceptions are: • Initial conditions questions, asked only once (e.g. school leaving age) – though in this case the variable is present at each wave, but only valid for some • Intermittent rotating questions • Variable components (e.g. wealth, life history) • Questions dropped as low priority • New questions ESRC UK Longitudinal Studies Centre

15. Types of BHPS data • Initial conditions / life histories • Repeated annual measures • Continuous history information (work, income, family) • Irregular topics, collected from variable components (e.g. wealth, ageing etc.) • Permits a range of different statistical methods, including panel repeated measures models and duration models. • Data files contain weights for a range of analysis, imputation for item non-response, and a considerable number of derived variables. ESRC UK Longitudinal Studies Centre

16. The BHPS and longitudinal research • BHPS supports a wide range of types of longitudinal research • Analysis of gross (individual level) change – inflow and outflow measures (e.g. employment and family status) • Inherently longitudinal phenomena (eg unstable employment, poverty persistence). • Controlling for unobserved characteristics • Causal inferences from temporal sequence – both short term and long term • Relationships between attitudes, expectations, preferences and behaviour • Analysis of quasi-experiments – impacts of policy ESRC UK Longitudinal Studies Centre

17. Examples of Research Using BHPS • Poverty and income dynamics / impacts of family change • Welfare in old age and wealth accumulation over the life course • Impacts of class or human capital on life chances • Scarring effects of unemployment and poor quality jobs on later employment • Impacts of life events on psychological well-being • Choice between marriage and cohabitation • Neighbourhood effects on social exclusion • Sharing of political attitudes within the household • Impacts of parental circumstances on child outcomes ESRC UK Longitudinal Studies Centre

18. BHPS data design • BHPS data comes in a series of separate files which reflect the way it was collected, and the main units of analysis at each wave – e.g. a file containing most data collect from each adult respondent. • These files can be linked by simple matching operations. These operations are aided by some basic file and variable naming conventions – common root name with wave specific prefix • Data are released using the same file structures for all software (SPSS, SAS, STATA, SIR • In addition to variables from the questionnaire there are large numbers of derived variables some of which aim to reduce the amount of file matching required. ESRC UK Longitudinal Studies Centre

19. Documentation • Extremely comprehensive and easily accessible documentation • PDF files are available from the Archive, but now easier to use web version: http://iserwww.essex.ac.uk/ulsc/bhps/doc • Volume A – descriptive information about survey and data. • Volume B – detailed variable lists, questionnaire info, marginals, links to other waves - this volume is indexed by wave and record type, and by subject thesaurus • Questionnaires are also available as PDF files for download. ESRC UK Longitudinal Studies Centre

20. Future data plans: variable components • Wave 14 (2004) National identity, views of UK governance, additional health measures (SF36), and measures of work attitudes and work stress. • Wave 15 (2005) Wealth, Assets and Debts – second measurement in Scotland • Wave 16 (2006) Ageing, retirement, health, and quality of life • Wave 17 (2007) Children and parenting, non-resident parents, aspirations of young people • Wave 18 (2008) Neighbourhood, expectations of relationships and marriage in the future ESRC UK Longitudinal Studies Centre

21. Other issues for the future • Sample size, re-sampling • Representation of migrants to the population • Linkage to contextual data – neighbourhoods, organisations (e.g. school, workplace) – how do we dal with disclosure risks? • Linkage to individual administrative data • New agendas for data collection e.g. health measurement, crime and victimisation • New methods of data collection (e.g. web-surveys) ESRC UK Longitudinal Studies Centre

22. More information • Documentation, including lists of publications based on BHPS available at http://www.iser.essex.ac.uk/ulsc/bhps • Also provides information on BHPS user group • Data from Economic and Social Data Service (Data Archive) http://www.esds.ac.uk ESRC UK Longitudinal Studies Centre