The UK Household Longitudinal Study

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The UK Household Longitudinal Study

• Nick Buck
• ISER, University of Essex

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Who we are the scientific leadership team

• Nick Buck (ISER, Essex) Principal investigator
• Randy Banks (ISER)
• Stephen Jenkins (ISER)
• Heather Laurie (ISER)
• Peter Lynn (ISER)
• Steve Pudney (ISER)
• Lucinda Platt (ISER) ethnicity strand
• Richard Berthoud (ISER) ethnicity strand
• Heidi Mirza (Institute of Education) ethnicity
  strand
• Dieter Wolke (Warwick) biomedical strand
• Scott Weich (Warwick) biomedical strand

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Structure of presentation

• Background and developments so far
• UKHLS objectives and key features
• Structure of UKHLS and constraints
• The UKHLS questionnaire
• Relationship to BHPS
• The consultation process
• Some general issues for consideration
• Timetable

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Background

• UKLHS is a longitudinal study based on a
  household panel design, i.e.
• sample based on all residents (adults and
  children) at addresses selected at wave one,
  following them at each wave, including movers and
  collecting data about new household members
• Basic design similar to that of British Household
  Panel Survey, which it will replace, and to
  panels in other countries, e.g. SOEP, HILDA,
  PSID, SoFIE so opportunities for comparison
• Target sample size of 40,000 households largest
  HPS

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Background (2)

• Major investment in the UKHLS is motivated by the
  success of longitudinal research in UK
• Most diverse portfolio of studies in the world
• In addition to BHPS Birth cohort studies (NCDS,
  BCS1970, MCS, ALSPAC), Studies of ageing (ELSA),
  Youth cohort studies (YCS, LSYPE), Census link
  studies and others
• Longitudinal research has had major impacts on
  both scientific research and policy research

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UKHLS informed by rationales for longitudinal
research

• Net versus gross change gross change visible
  only from longitudinal data
• e.g. decomposition of change in unemployment rate
  over time into contributions from inflows and
  outflows
• Some phenomena are inherently longitudinal (e.g.
  poverty persistence unstable employment)
• Provides spell-based perspectives (and can
  observe how circumstances change with time spent
  in state)
• Repeated observations on individuals allow for
  possibility of controlling for unobserved
  differences between individuals (fixed and random
  effect models)
• The ability to make causal inference is enhanced
  by temporal ordering

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Developments so far

• ESRC secured funding from OSI to start UKHLS
• Expert Panel (chair Peter Elias) steered
  development of UKHLS up to appointment of PI team
• 4 expert studies made recommendations on content
  and design presented at meeting in October 2006
• November 2006 March 2007, commissioning of
  principal investigator team
• From April 2007, PI team starts work with
  consultation and commission survey organisation
• ESRC continues to seek co-funding

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Key features of UKHLS

• The following should be exploited and shape the
  priorities for topic content
• Large sample size proposed
• Household focus of the design
• Full age range sample
• Innovative data collection methods
• Multi-purpose multi-topic design to meet a wide
  range of disciplinary and inter-disciplinary
  research needs
• Ethnic minority research
• Biomedical research.

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Key features large sample size

• 40,000 households gives an opportunity to explore
  issues where other longitudinal surveys are too
  small.
• Small subgroups, such as teenage parents or
  disabled people.
• Analysis at regional and sub-regional levels,
  allowing examination of the effects of
  geographical variation
• Large sample size allows high-resolution analysis
  of events in time, for example focussing on
  single-year age cohorts.

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Key features household focus

• Data collected on all members of sampled
  households
• Important for research on e.g.
• consumption and income, where within-household
  sharing of resources is important,
• demographic change, where the household itself is
  often the object of study.
• Can investigate family factors in decision making
• Observing multiple generations allows examination
  of long-term transmission processes
• Comparative analysis of sibling outcomes
• Opportunities to explore linkages outside the
  household

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Key features full age range

• The UKHLS sample includes full age range at any
  point in time so complements age-focused
  studies sampling elderly people (e.g. ELSA) or
  young people (e.g. birth cohort studies)
• Provide a unique look at behaviours and
  transitions in mid-life e.g. for issues of
  pensions and long-term care, associated with old
  age, policy setting is influenced by earlier
  behaviour.
• Large sample size means that all cohorts can be
  analysed at a common point in time.

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Key features innovative data collection

• Continuous development in data collection methods
  benefiting from
• experience from other longitudinal surveys,
• the introduction of new technologies.
• This will involve e.g.
• additional modes of interviewing,
• collection of qualitative and visual data,
• external record linkage
• Innovation Panel to allow experimentation and
  methodological development.

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Key features broad interdisciplinary topic
coverage

• UKHLS will be multi-purpose survey supporting a
  very wide range of research agenda
• which means it cannot have the focus in depth
  that more specialist surveys can achieve
• Strength arises from bringing together
  information on many life course domains
• Interdisciplinary aims both to meet needs of
  traditional panel use disciplines (economics,
  social policy and sociology) and support more
  interdisciplinary work within the social sciences
  (e.g. geography and economics) within the
  biomedical sciences (e.g. psychology and
  genetics) and between the two.

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Key features ethnic minority research

• Ethnicity strand includes
• Boost sample for five key groups (Indian,
  Pakistani, Bangladeshi, Carribean, Black African)
• Questions focused on ethnicity issues
• Recognises the increasing prominence of research
  into ethnic difference for understanding the
  make-up of British society and issues of
  diversity and commonality.

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Key features biomedical researh

• UKHLS will support collection of a wide range of
  biomarkers and health indicators
• Opportunity to assess exposure and antecedent
  factors of health status, understanding disease
  mechanisms (e.g. gene-environment interaction,
  gene-to-function links), household and
  socioeconomic effects and analysis of outcomes
  using direct assessments or data linkage.
• Opens up prospects for advances at the interface
  between social science and biomedical research.

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UKHLS study design

• Start with a sample of addresses, all members of
  private households found will be sample members.
• At each wave all sample members above a threshold
  age eligible for interview.
• Other individuals who form households with sample
  members after wave 1 eligible for interview.
• UKHLS will be a longitudinal sample of
  individuals representing the whole UK population,
  and interviewed within a household context.
• Individuals followed as they move and form new
  households.
• Following rules mean that the UKHLS will remain
  representative of the UK population as it
  changes, subject to weighting and except for new
  immigrants to the UK.

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UKHLS sample consists of

• A new equal probability main panel achieved
  sample of 28,000 - 29,000 households. The
  fieldwork for this sample will commence in
  January 2009
• A boost ethnic minority sample, to provide 1,000
  adult individuals in each of the five main ethnic
  minority groups
• The BHPS sample of approximately 8,400
  households. BHPS sample data collection as part
  of the UKHLS will start with wave 2 in October
  2009
• An Innovation Panel of 1500 households to enable
  methodological research. The fieldwork for the
  Innovation Panel will commence in January 2008.

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UKHLS design

• Some aspects remain to be finalised and depend
  partly on co-funding. The following are expected
• 12 month intervals between interviews
• Continuous fieldwork (implications for reference
  periods for retrospective questions) Possible 24
  month field period, with second wave overlapping
  with first
• Face-to-face interview at wave 1 mixed mode at
  wave 2
• Wave 1 individual interview not more than 40
  minutes, wave 2 depends on budget, unlikely to
  exceed 40 minutes and may be shorter
• Some data collection from children aged less than
  16 not clear when this would start

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The UKHLS questionnaire

• Length constraints are likely to be particularly
  acute, given broad scope of UKHLS and wide range
  of demands
• So move away from BHPS structure where most
  people are eligible to be asked all questions and
  most questions repeated each wave
• More use of questions asked regularly, but not
  every wave
• More use of questions asked only after key events
  or at particular ages
• More use of sub-samples, perhaps random
  sub-samples, where full sample unnecessary, or
  demographic sub-samples

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Structure of the UKHLS questionnaire
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BHPS and UKHLS

• At wave 2 of UKHLS (wave 19 of BHPS), the BHPS
  sample will become part of UKHLS
• Expected that BHPS will use new questionnaire
  from that point (with very limited modification
  to preserve some measurement continuity)
• Development process recognised importance of
  comparability with BHPS so likely to be
  significant use of BHPS questions in UKHLS
• But, likely that a high proportion of BHPS
  questions will not be included, or will be asked
  less frequently

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Consultation on UKHLS content

• Key aims are to establish
• 1) the priorities for inclusion in the UKHLS,
• 2) the content of the core questionnaire (i.e.
  that part intended to be repeated at each wave),
  and
• 3) the content and sequencing of modules which
  might be included less frequently, or only be
  addressed to part of the sample.
• Objective is to consult as widely as possible,
  within the constraints of the timetable (more on
  this later)
• Particular objective to go beyond current
  longitudinal study users, and identify new areas

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Methods of consultation

• Topic groups (next slide)
• Ethnicity strand consultation
• Advisory committees and Governing Board
• Using UKHLS web site to make documents on design
  available
• Targeted consultation with e.g. government
  departments, ESRC Boards and Directors, other
  research councils
• Encouraging comments from any interested parties

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Topic consultation groups

• Standard of living measures (income, consumption,
  material deprivation, expenditure, financial
  well-being)
• Family, social networks and interactions, local
  contexts, social support, technology and social
  contacts
• Attitudes and behaviours related to environmental
  issues (energy, transport, air quality, global
  warming etc.)
• Illicit and risky behaviour (crime, drug use,
  anti-social behaviour etc).
• Lifestyle, social, political, religious and other
  participation, identity and related practices,
  dimensions of life satisfaction/happiness
• Psychological attributes, cognitive abilities and
  behaviour
• Preferences, beliefs, attitudes and expectations
• Health outcomes and health related behaviour
• Education, human capital and work
• Initial conditions, life history

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Topic groups

• We do not expect topic groups to be designing
  questions or questionnaire sections we are
  expecting them to identify measures and to
  justify their importance in terms of key research
  agenda
• Topic group first meetings taking place between
  25 June and 18 July,
• Over the summer expected to continue business,
  mainly electronically
• Convenors will be summarising conclusions
  questionnaire design team will have access to all
  comments received
• Topic group cover may not be exhaustive some
  research areas may be missing. Let me know about
  those which concern you particularly.

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Some cross-cutting issues for most topic groups

• What is the optimal data collection frequency for
  measures from a research perspective?
• What level of detail is really required?
• For retrospective and flow measures what is the
  most appropriate reference period?
• To what extent is it necessary to collect
  information about each individual within the
  household?
• To what extent can data be reliably collected by
  one respondent on behalf of all others in the
  same household?

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More cross-cutting issues

• How important is continuity of measurement
  relative to the existing BHPS, and comparability
  with other UK national surveys?
• To what extent is cross-national comparability an
  important consideration when choosing a measure?
• To what extent can linkage with administrative
  and other data sources provide data that can
  substitute or complement collection of that data
  within the UKHLS?

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Mode of data collection

• Most likely for UKHLS face-to-face, telephone,
  web
• Main differences between modes
• Visual vs. aural transmission of information
• Cognitive stimulus of survey question
• Self- vs. interviewer administered
• Who controls pace and flow of survey, possibility
  of respondent multitasking
• Face-to-face presence of interviewer
• ? Potential for non-verbal communication between
  interviewer and respondent, privacy of reporting
  situation, rapport, pace of interview
• These lead to differences between modes in
• Task difficulty
• Respondent motivation to make required effort
• Willingness to disclose (sensitive) information
• ? Potential differences in measurement across
  modes

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Example Face-to-Face vs. Telephone
Face-to-Face Telephone
Showcards Long lists Check all that apply Complex scales with word labels for each scale point Short lists / branched Qs Series of yes/no Qs Scales anchored in numeric endpoints Simpler/shorter Qs
Interviewer Non-verbal communication Probes to open-ended Qs Rapport Non-verbal measurements Verbal communication only Probes to open-ended Qs Different approach to rapport
Potential problems Primacy effects (first categories) Social desirability bias Recency effects (last categories) Social desirability bias More superficial cognitive processing
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Respondent burden issues

• UKHLS will involve repeated contacts with sample
  members
• The better the experience at any wave the more
  likely take part next wave particularly
  important at first wave and other early waves
  until some commitment to study is established
• Therefore
• First wave cannot be too long
• Avoid subject matter which is likely to be very
  sensitive
• Minimise subject matter likely to be
  uninteresting to respondents (though different
  respondents have different interests!)

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Timetable
May-July 2007 Recruitment to topic consultation groups and first meetings
September 2007 Feedback from topic groups on core content, to contribute to questionnaire content for the Innovation Panel
September/October 2007 First meetings of Scientific Advisory Committee and Governing Board
December 2007 Consultation on wave one content concluded consultation on future waves continues.
January 2008 Plenary conference
January December 2008 and beyond Consultation on wave two and future wave content we anticipate that the topic groups would remain active
June 2008 Final survey pre-test for wave one
January 2009 Start of wave one main fieldwork
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• Web http//www.iser.essex.ac.uk/ukhls
• Email comments to
• ukhls-consult_at_isermail.essex.ac.uk