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Webinar structure
• 40 minute presentation
• 20 minutes for questions and answers
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• Some questions for the audience during presentation
Your presenters
Dr. Oliver Duke-Williams
Senior Adviser, CeLSIUS, and:
Lecturer in Digital Information Studies
UCL
[email protected]
Rachel Stuchbury
Support Officer, CeLSIUS
UCL
[email protected]
We will cover:
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What are the Longitudinal Studies?
What kinds of research are they useful for?
How can you access them?
What support is available?
But first:
Economic activity in the East Midlands
2001 and 2011
MEN
Census year
WOMEN
2001
2011
2001
2011
Age group
18-54
28-64
18-54
28-64
Employed: more
autonomy
34%
33%
37%
41%
Employed: less
autonomy
36%
32%
26%
21%
Self-employed
12%
16%
5%
7%
Seeking work
5%
4%
3%
4%
Inactive
13%
15%
29%
27%
100%
100%
100%
100%
TOTAL
What happened to the men seeking work or inactive in 2001 – were they working in
2011? Did they become self-employed?
The proportion of women in jobs with less autonomy went down – what happened to
them? Did they move to higher-level jobs?
We need longitudinal data!
What brings you here?
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1
I want to use longitudinal data
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4
I want to analyse quantitative data
I want to use the Longitudinal Studies
OR…are you here for other reasons?
The Longitudinal Studies (LSs)
For England and Wales:
The Office for National Statistics’ Longitudinal Study (ONS-LS)
For Scotland:
The Scottish Longitudinal Study (SLS)
For Northern Ireland:
The Northern Ireland Longitudinal Study (NILS)
The Core Data Sources
• Census data – linked at individual level BUT including data for
the whole household
England & Wales
1971
1981
1991
2001
2011
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Scotland
Northern Ireland
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• Data from registration of life events
England and Wales: birth, birth of child to mother, widowhood,
cancer diagnosis, death
Scotland: same plus marriage and birth of child to father
Northern Ireland: as Scotland
• PLUS!! For Scotland and Northern Ireland, many additional data
sources are available
Census topics
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Geography
Housing tenure
OR type of communal
establishment
Sex and age
Ethnicity / country of birth
Qualifications
Marital status
Family composition
Economic activity
Occupation / social class
Migration
Travel to work
Chronic illness
New in 2001
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Religion
Self-rated health
Care-giving
Year last worked
New in 2011
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National identity
Passports held (not Scotland)
When arrived in UK
Main language / fluency in English
Chronic conditions – specified (not England/Wales)
Voluntary work (N. Ireland only)
For more detail look at the individual forms http://calls.ac.uk/guides-resources/census-forms/
The Scottish Longitudinal Study (SLS)
The Northern Irish Longitudinal Study (NILS)
Contextual data
1981 Census
1991 Census
2001 Census
2011 Census
NILS Core data
Events
Health Card
registrations
(includes new
members)
Household
Characteristics
Area
Characteristics
Vital events:
births, deaths
NILS
databases
Migration
data
Property
Characteristics
Individual
project
datasets
For Distinct Linkage
Projects Health &
Social Care data
can be securely
linked to NILS (using
one‐way encryption
methods)
The samples
• Samples selected by birthday (irrespective of year of birth)
England & Wales
Scotland
Northern Ireland
1971
1991
Health card registration
system 2001, followed up
retrospectively from 1981
4 birthdates
20 birthdates
104 birthdates
Sampling fraction
~1%
~5%
28%
n at 2011
580k
270k
500k
Initial sample
drawn from
Selection
Therefore possible to analyse very small geographies or other small groups
Also note the Northern Ireland Mortality Study: 100% sample, links deaths
since 1991 to census data from 1991, 2001 and 2011.
Entry and exit
Entry to the study is by :
 being born, OR
 registering with the health service, OR
 being enumerated at census and not previously in the LS
AND, in all cases, having a sample birthday.
Exit (suspension) from the study is by:
 dying, OR
 de-registering from the health service (but re-registration
activates the sample membership again)
ALL records retained permanently for analysis
e.g. Woman
Birth of
Child
included from 1971 Census in LS
Death of
Spouse
Birth of
Twins
Cancer
Death
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1971
1976
1981
1986
1991
1996
2001
2006
2011
Census
Census
Census
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Census
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Census
Types of study design using the
Longitudinal Studies
1.
(Repeated) cross-sectional: at each census (1971-2011)
2.
Geographical: Small area, regional and national comparisons
3.
Longitudinal: following same people at 2+ Census points
4.
Longitudinal events: fertility, cancer incidence & mortality by
census characteristics before & after the event
5.
Cross-sequential: comparing change in two cohorts (e.g. class
mobility 1971 to 1991 with class mobility 1981 to 2001)
6.
Inter-generational: (eg parental characteristics of sample members
in earlier census by their own characteristics in later census)
e.g.
Longitudinal:
Intercensal change 1991 to 2001
“How stable were cohabiting partnerships compared to
married partnerships between 1991 and 2001?”
 Study population: people aged 16-54 who were married or cohabiting
in 1991 and present at Census in 2001
Question:
Which age group (in 1991) is most likely to have NO partner ten
years later?
Partnership status 1991 and 2001 by age in 1991
 Population: people aged 16 to 54 in 1991
e.g.
Longitudinal:
Census plus events
“Do teenage mothers suffer social disadvantage,
either before or after their early motherhood?”
 Study population:
Women aged 5 to 9 years at 1981,
Also present at 2001,
Using ‘live birth to sample mother’ records to identify first birth.
n=13,408
“Do teenage mothers suffer social disadvantage, either
before or after their early motherhood?”
 Women aged 5 to 9 years at 1981, present at 2001
e.g.
Longitudinal:
Intergenerational
“Do middle‐aged adults in 2001 tend to occupy a similar social class to that of their parents in 1971?”
 Study population: those aged 6-15 in 1971, also present at the 2001
Census; n=24,898
Question:
For unemployed men aged 36-45 in 2001 –
What is the most common status for their parent thirty years earlier?
Highest Social class of parents in 1971 (2 parents) by
Social class of LS sample members (36-45) in 01 (Men)
Percentage
50
40
30
20
I&II
10
III Non
0
III Man
I&II
III Non
III Man
IV&V
U/E
Other
Inact
Social class of LS sample members in 2001
(Males)
IV&V
U/E
Other Inact
How to access Longitudinal Study data
Each Longitudinal Study has different arrangements but they all involve the
same steps:
• Formulate your research question
• Contact the appropriate Support Unit to discuss your proposal
• Work with Support Officers to complete and submit the project application
form
• Apply for Approved Researcher status
• Attend Safe Researcher training (if planning to work in safe setting)
• Work in a safe setting on your analyses
• England and Wales: London, Titchfield (Hampshire), Newport (Wales)
• Scotland: Edinburgh
• Northern Ireland: Belfast
• or (not N. Ireland) send code for Support Officers to run on your behalf
• Receive cleared output by encrypted email
• Submit all outputs from your work for clearance prior to publication
The Support Units
For England and Wales: CeLSIUS
(Centre for Longitudinal Study Information and User Support)
http://www.ucl.ac.uk/celsius
For Scotland: SLS-DSU
(Scottish Longitudinal Study Development & Support Unit)
http://www.lscs.ac.uk/sls
For Northern Ireland: NILS-RSU
(Northern Ireland Longitudinal Study Research Support Unit)
http://www.qub.ac.uk/research-centres/NILSResearchSupportUnit/
For all three + UK-wide resources (unified Data Dictionary): CALLS-HUB
(Census and Administrative Data Longitudinal Studies Hub) http://calls.ac.uk/
UK LS?
All three user support units and statistical offices are working together with ESRC to make UK research possible
Some examples of this
• Calls‐Hub – one stop shop for an introduction to the three LSs www.calls.ac.uk
• Edata shield ‐a technical resource for modelling with comparable data from all three LSs • SYLLS ‐ synthetic longitudinal data akin to real data preserving the relationships between variables and transitions of individuals over time –OGL release • SYNTHPOP R tool for generating synthetic versions of sensitive microdata for statistical disclosure control
• Cross LS harmonised data dictionary
The England/Wales Study (ONS LS)