Quantitative methods for researching lives through time

Heather LaurieInstitute for Social and Economic

ResearchUniversity of Essex

laurh@essex.ac.uk

Overview What do we mean by longitudinal? Distinguish method from design Cohort and panel designs What can quantitative longitudinal

studiestell us?

Introduce a new study – Understanding Society

Defining ‘longitudinal’ Term that encompasses many forms

of data and many designs Used as a catch-all for any study

that has some element of time within it

From oral histories through to qualitative analysis of life-course events and transitions

And to quantitative panel or cohort analysis of repeated observations of the same cases

Defining ‘longitudinal’

Who or what are we following? For what time period? How often?

Defining ‘longitudinal’ Common factors regardless of

methodology Information at or about more than one

point in time Research questions that are inherently

longitudinal in natureunderstanding the antecedents of eventsprocess and lived experience influences on decision-makingthe timing of transitions from one state to

another

A longitudinal research focus Inherently longitudinal research

questions e.g.Educational and employment outcomes

for children depending on family and social background

Labour market transitions and the impact on life time earnings, career progression and well-being

Impact of ethnicity and gender on long-term outcomes in the labour market and family life

Inter-generational transmission of attitudes, values, deprivation, wealth

Analysis across the life-course A longitudinal perspective on change

in individuals’ lives over time Recognises complex interactions

between life course domains e.g. work, living arrangements, income, leisure, health

Importance of social context e.g. household, wider social networks, local environment, and social and cultural norms.

Method or design? The design of any study depends on

the research questions you want to answer

The method you use to collect those data depends on many elements cross-sectional or longitudinalthe population of interestgeneralisation to a population vs case

studythe type of analysis needed to answer

your research questions

Quantitative design approaches Retrospective studies

Past events and transitions are recalled by respondents e.g. life time employment history

Record linkage panels From data collected for administrative

purposes e.g. taxation or social welfare system

Prospective studies Produce ‘waves’ or ‘sweeps’ of

measurement collected over a period of years

Cohort studies Often birth cohorts e.g. MCS but can be any age

group/ ELSA aged 50+ Follow up same cohort members at fairly long

intervals - e.g. NCDS now every 4 years; ELSA every two years

Birth cohorts include developmental data as well as social and economic data

Triangulation of data from parents, teachers, schools associated with cohort member

Allow observation of long-term outcomes with detailed information on childhood and family circumstances

Household panels Draw a sample at one point in time and

follow those sample members indefinitely Collect individual level data in household

context Usually interview all members of the

household Repeated measures at fixed intervals

(usually annual data collection) Annual data collection allows analysis of

short-term change Indefinite life design allows longer-term

outcomes to be observed

What do quantitative longitudinal panels offer?

Temporal information on sequence of events

Allows us to make better inferences about cause and effect

Short term dynamics of change Long term dynamics Links between current events and

outcomes and past history

What do quantitative longitudinal panels offer? Repeated observations on the same

individual controls for the effects of unmeasured heterogeneity between cases

Reduce recall error Can better understand social change

by separating out age, period and cohort effects

To establish the effect of a treatment Sampling techniques mean statistical

findings can be generalised to the whole population

Understanding Society A new household panel for the UKKey features: Large sample size of 40,000

households Includes all of UK Household focus with full age range

sample Annual interviews with all aged 10 and

over Innovation Panel for methodological

research and testing

Key features(cont) Multi-topic design to meet a wide

range of disciplinary and inter-disciplinary research needs

Ethnic minority research Biomedical research Data linkage to administrative

records Opportunities for qualitative linked

studies

Annual repeating content Basic demographic

characteristics Changes between waves -

employment, fertility, partnering, geographic mobility, health

Health status (e.g. SF12), disability,

Labour market activity and employment status, job search

Current job characteristics, basic employment conditions, hours of paid work, second jobs

Childcare, other caring within and outside household

Income and earnings Life satisfaction Political affiliation – basic

measures Transport and

communication access Education aspirations and

expectations Consumption expenditure Housing characteristics –

basic Housing expenditure Household facilities, car

ownership

Understanding Society rotating content Family and social networks outside the household Attitudes and behaviours related to environmental

issues Illicit and risky behaviour especially for young people Psychological attributes Cognitive ability measures Health outcomes and health related behaviour Quality of sleep Well-being Quality of marital relationships Risk and trust Collection of data about younger children < 10 Transition into young adulthood Discrimination and harassment Ethnic and national identity

Ethnic minority research Boost sample for five key groups in the

UK (Indian, Pakistani, Bangladeshi, Caribbean, Black African, Mixed)

Increasing prominence of research into ethnic difference for understanding the make-up of UK society

Focus on issues of diversity and commonality.

Common questionnaire content across the sample for many questions

Additional questionnaire content within the ethnic minority boost

Linkage to administrative records

Ask respondents for permission to link to: Health records and hospital episodes statistics Education records Pension and state benefit records

Parents asked for permission on behalf of children < 16

Link to pupil level and school level education data each pupil in England has a Unique Pupil Number so can

follow as they progress through the school system

Link survey data to a range of geo-coded data, including environmental data

Biomedical research Collecting 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),

household and socioeconomic effects, analysis of outcomes using direct

assessments or data linkage.

Opens up prospects for advances at the interface between social science and biomedical research.

Research potential

Developed as a research resource for the whole user community

First data available from the UK Data Archive from early 2011

Like the British Household Panel Study(BHPS), we hope it will be widely used

ISER publications and web contact For further information about

Understanding Society see www.understandingsociety.org.uk

For ISER publications and Working Papers see www.iser.essex.ac.uk/publications