1. EU-SILC from a Research Perspective
Heike Wirth & Christof Wolf

2. Topics covered Strengths of EU-SILC Flexible implementation of EU-SILC
Selected issues regarding data comparability
Opportunities for longitudinal analysis with EU-SILC

3. Strengths of EU-SILC Coverage of countries Coverage of topics
(Private) Household survey
Cross-sectional and longitudinal data
Good and improving data documentation
Access for research purposes free of charge (but more demanding under new regulation)

4. Flexibility

5. Flexible implementation of EU-SILC
EU-SILC is based on a common framework
guidelines: concepts, definitions, classifications, procedures
Target variables, i.e. ex ante harmonization
Within this framework high flexibility regarding data generation
Accommodates the national conditions and needs (+)
Potential to limit cross-national comparability (–)
While the input side might be diverse, the output side is harmonized (standardized microdata set)
i.e. problems of data comparability are not directly visible

6. Flexible implementation of EU-SILC
Some potential sources of non-comparability
Different sampling strategies
Different survey designs
Different modes of data collection
Different field work periods and procedures
Different national questionnaires
Different reference periods
Different nonresponse rates
Different attrition rates …

7. Comparability

8. Why is comparability so important?
EU-SILC is the central data source for social reporting in Europe
Social indicators based on EU-SILC are used
to assess countries’ places in relation to each other
to learn from others’ best practices
to evaluate policy measures

9. Selected issues regarding data comparability
1. Different survey designs and response rates 2. Different modes of data collection 3. Ex-ante output harmonization: Wording of questions

10. Comparability 1: Survey design and response rates
Rotational panel: variations across countries in the number of rotations. Most countries 4, but 8 in NO, 9 in FR and full panel in LU (in the future possibly 6 or more waves)
Response rates and attrition vary throughout Europe

11. SILC response rates 2007 (only new rotational group)
Source: Eurostat: Proposal for revising the design of EU-SILC longitudinal component. Item 4; 5th Meeting of the Task-Force on the revision of the EU-SILC legal basis.

12. EU-SILC retention rates (a) households, (b) individuals re-interviewed the following year, in %
Source: Iacovou et al (2012) from EU-SILC longitudinal files, release , unweighted

13. Comparability 2: Different modes of data collection
Sources of EU-SILC data could be:
survey(s)
register(s)
combination of survey(s) & register(s)
Data could come from one source or two sources
Issue of concern: Substantial findings of EU-SILC such as indicators used in social reporting may differ due to the diversity in the data collection across countries

14. Different modes of data collection (2010)
Information/
Interview completed from
Survey
73.1%
Survey countries
BE, BG, CY, CZ, DE, GR, ES, EE, FR, HU, IT,LT, LU, MT; AT, PL, PT, RO, SK, UK
Register
3.4%
Both: Survey & Register
22.8%
Register countries
DK, FI, SE, NL, IS, LV, SI, IE
Full Record Imputation
0.7%

15. Use of registers for different domains

16. Different modes of data collection
Measures in surveys and registers may be based on different concepts, e.g.
Earnings information in registers
tax-based (non taxed earnings?)
different points in time when income and tax are collected (self-employed, temporary workers)
Employment, Unemployment
evidence that information on unemployment in survey and registers differ in a significant way at the individual level
survey: e.g. memory errors regarding employment situation in the past
Consistency problems if combining information from different sources?

17. Different modes of data collection
Mixed modes of data collection in surveys
Personal interview (respondent)
CATI (Computer Assisted Telefon Interview)
CAPI (Computer Assisted Personal Interview)
PAPI (Paper and Pencil Personal Interview)
self-administered (respondent completes the questionnaire him/herself)
Proxy-interview (respondent has someone else answer the questions for him/her)
Type of interview might affect the response and thus reduce the comparability between countries and for countries with sequential mixed mode between waves

18. Different modes of data collection (2010)
SURVEY COUNTRIES
Interview
73.1%
Face to Face
CAPI 29.1%
PAPI 42.3%
CATI
3.9%
Self-administered
5.5%
Proxy Interview
18.3%
REGISTER COUNTRIES
Register & Interviews
22.8%
CAPI %
PAPI 11.7%
65.6%
0.4%
22.0%

19. Proxy interview by country – ‘register countries’
% of proxy interviews
 Country
proxy interview
Iceland
0.0
Nederland
1.2
Sverige
2.1
Ireland
23.7
Latvia
Norway
23.8
Slovenia
24.6
Suomi
42.7
Danmark
48.6
Datasource: UDB_c10R_ver from , own computation
As a rule only 1 person in hh is interviewed, who answers also for all other hh members

20. Proxy interviews by country – ‘survey countries’
% of proxy interviews
Slovak Republic
4.3
Czech Republic
19.3
Ellada
8.0
Hungary
19.8
Belgique
8.6
Luxembourg
20.1
United Kingdom
10.7
Bulgaria
20.3
Oesterreich
13.7
Portugal
20.5
Romania
15.3
Espana
21.9
Lithuania
15.6
Cyprus
23.0
Deutschland
18.8
Estonia
24.3
Italia
19.0
France
27.6
Poland
19.2
Malta
28.9
Datasource: UDB_c10R_ver from , own computation

21. Flexibility in modes of data collection
Quality of proxy interviews might depend on the reason of the proxy interview
a respondent is not accessible or willing to give an interview
proxy interview are cofounded with other characteristics like age or sex
producers take proxy interviews as a mean to lower costs
data producers might make efforts for a random selection of proxy respondents

22. Comparability 3 – Different questionnaires
SILC is ex ante harmonized, i.e. variables which are delivered by the NSIs to Eurostat are defined in regulations & guidelines (=> standard EU-SILC definition)
But there is no common SILC questionnaire
questionnaire design varies (e.g. order of questions)
wording of questions varies (e.g. ‘How often do you usually ..’ or 'How often during a usual year do you …?)

23. Research example
Research example Gash (2011): Methodological issues in comparative research. European Workshop to Introduce the EU-SILC and EU-LFS Manchester
Research interest
How does unemployment affect social engagement?
EU-SILC Module (2006) on Social Participation
Frequency of contacts/getting together with friends &relatives
Ability to ask relatives, friends, neighbours for help
Participation in formal and informal activities
Participation in cultural/sport events o
o PS090 - Ability to ask any relative, friend or neighbour for help
o PS100 - Participation in informal voluntary activities
o PS110 - Participation in activities of political parties or trade unions
o PS120 - Participation in activities of professional associations
o PS130 - Participation in activities of churches or other religious organisations
o PS140 - Participation in activities of recreational groups or organisations
o PS150 - Participation in activities of charitable organisations
o PS160 - Participation in activities of other groups or organisations

24. Research example Main findings:
Broad agreement in the questionnaire wording across countries, but
Some countries provide examples of social participation others not
Some countries mention reference periods others not
Some countries prompt that respondents should exclude people they live with others not
Might have an effect on the reported frequencies of contacts

25. Source: Gash, Vanessa (2011): METHODOLOGICAL ISSUES in COMPARATIVE RESEARCH

26. Comparability 3 - Output harmonization
When Eurostat knows about problems arising from different wording or other deviations in the questoinnaire it reports this
Most national questionnaires are available
Check documentation!!!

27. Opportunities for Longitudinal Analysis with EU-SILC

28. Opportunities for Longitudinal Analysis
Main topics studied with SILC (Eiffe & Till 2013)
Income studies
Poverty studies
Labour market studies
Limitations arise because SILC is a short-term panel, i.e. a maximum of 3 transitions

29. Income studies Income distribution
What are the consequences of income gains and losses on income inequality and poverty levels?
How do regional economic and labour market structures as well as national institutions contribute to changes of income level and income distribution?
Income dynamics
How much does income mobility vary across European countries?
See: Franz F. Eiffe and Matthias Till The Longitudinal Component of EU‐SILC Still Underused? NetSILC2: Working Paper 1/2013.

30. Income studies Impact of socio-economic events on income
Impact of having a disabled person in a household
Changes in women’s contribution in Italian families
Effect of partnership breakdown on individual income
See: Franz F. Eiffe and Matthias Till The Longitudinal Component of EU‐SILC Still Underused? NetSILC2: Working Paper 1/2013.

31. Poverty studies
How long do individuals or households remain in poor living conditions?
How often do Europeans experience poverty over their life span (or at least over four years)?
What are the profiles of households who remain in poverty for longer periods?
What are the events/determinants that trigger poverty transitions?
See: Franz F. Eiffe and Matthias Till The Longitudinal Component of EU‐SILC Still Underused? NetSILC2: Working Paper 1/2013.

32. Labour market studies
What patterns of occupational mobility can be observed in Europe?
How difficult is it to leave unemployment?
How do labour market dynamics differ across countries?
Can difference between countries be explained by different institutions, e.g. welfare state arrangements?
See: Franz F. Eiffe and Matthias Till The Longitudinal Component of EU‐SILC Still Underused? NetSILC2: Working Paper 1/2013.

33. Possible problems of SILC longitudinal
Different attrition rates could be a problem
If there is a correlation between attrition and income or others variables this would be a problem However, income bias related to attrition seems to be low

34. Household participation in SILC by Income Quintiles in previous year
Source: Eurostat: Proposal for revising the design of EU-SILC longitudinal component. Item 4; 5th Meeting of the Task-Force on the revision of the EU-SILC legal basis.

35. Thanks for listeing!