EU-SILC from a Research Perspective

Heike Wirth & Christof Wolf

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• Strengths of EU-SILC• Flexible implementation of EU-SILC• Selected issues regarding data comparability• Opportunities for longitudinal analysis with EU-SILC

Topics covered

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• 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)

Strengths of EU-SILC

Flexibility

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• 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

Flexible implementation of EU-SILC

Some potential sources of non-comparability(1) Different sampling strategies (2) Different survey designs(3) Different modes of data collection(4) Different field work periods and procedures(5) Different national questionnaires(6) Different reference periods(7) Different nonresponse rates(8) Different attrition rates

…

Flexible implementation of EU-SILC

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Comparability

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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

Why is comparability so important?

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1. Different survey designs and response rates2. Different modes of data collection3. Ex-ante output harmonization: Wording of questions

Selected issues regarding data comparability

• Survey design• 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

Comparability 1: Survey design and response rates

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SILC response rates 2007 (only new rotational group)

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BE HU LV ES UK PL CZ EE AT DE SI BG FI EL IT IS MTNL CY FR PT RO SE SK DKNO0

20

40

60

80

100

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.

EU-SILC retention rates (a) households, (b) individuals re-interviewed the following year, in %

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UK SI NL DK IE SP HU EL FR PT PL FI CY RO70

75

80

85

90

95

100

% of eligible households in which at least one member was interviewed the next year% of eligible individuals in the sample who were interviewed the next year

Source: Iacovou et al (2012) from EU-SILC longitudinal files, release 2008-4, unweighted

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

Comparability 2: Different modes of data collection

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Different modes of data collection (2010)

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Information/Interview completed from

Survey73.1%

Survey countriesBE, 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 countriesDK, FI, SE, NL, IS, LV,

SI, IE

Full Record Imputation

0.7%

Use of registers for different domains

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• 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?

Different modes of data collection

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• 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

Different modes of data collection

Different modes of data collection (2010)

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SURVEY COUNTRIESInterview

73.1%

Face to Face• CAPI 29.1%• PAPI 42.3%

CATI 3.9%

Self-administered5.5%

Proxy Interview18.3%

Proxy interview by country – ‘register countries’

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% of proxy interviews

Country proxy interviewIceland 0.0

Nederland 1.2

Sverige 2.1

Ireland 23.7

Latvia 23.7

Norway 23.8

Slovenia 24.6

Suomi 42.7

Danmark 48.6

Datasource: UDB_c10R_ver 2010-2 from 01-08-12, own computation

As a rule only 1 person in hh is interviewed, who answers also for all other hh members

Proxy interviews by country – ‘survey countries’

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% of proxy interviews

Slovak Republic 4.3 Czech Republic 19.3Ellada 8.0 Hungary 19.8Belgique 8.6 Luxembourg 20.1United Kingdom 10.7 Bulgaria 20.3Oesterreich 13.7 Portugal 20.5Romania 15.3 Espana 21.9Lithuania 15.6 Cyprus 23.0Deutschland 18.8 Estonia 24.3Italia 19.0 France 27.6Poland 19.2 Malta 28.9Datasource: UDB_c10R_ver 2010-2 from 01-08-12, own computation

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• Quality of proxy interviews might depend on the reason of the proxy interview

1. a respondent is not accessible or willing to give an interview • proxy interview are cofounded with other characteristics like

age or sex

2. producers take proxy interviews as a mean to lower costs• data producers might make efforts for a random selection of

proxy respondents

Flexibility in modes of data collection

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• 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 …?)

Comparability 3 – Different questionnaires

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 events23

Research example

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Main findings: • Broad agreement in the questionnaire wording across

countries, but

1. Some countries provide examples of social participation others not

2. Some countries mention reference periods others not3. Some countries prompt that respondents should exclude

people they live with others not

Might have an effect on the reported frequencies of contacts

Research example

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

• 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!!!

Comparability 3 - Output harmonization

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Opportunities for Longitudinal Analysis with EU-SILC

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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

Opportunities for Longitudinal Analysis

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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?

Income studies

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See: Franz F. Eiffe and Matthias Till. 2013. The Longitudinal Component of EU‐SILC Still Underused? NetSILC2: Working Paper 1/2013.

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

Income studies

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See: Franz F. Eiffe and Matthias Till. 2013. The Longitudinal Component of EU‐SILC Still Underused? NetSILC2: Working Paper 1/2013.

• 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?

Poverty studies

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See: Franz F. Eiffe and Matthias Till. 2013. The Longitudinal Component of EU‐SILC Still Underused? NetSILC2: Working Paper 1/2013.

• 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?

Labour market studies

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See: Franz F. Eiffe and Matthias Till. 2013. The Longitudinal Component of EU‐SILC Still Underused? NetSILC2: Working Paper 1/2013.

• 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

Possible problems of SILC longitudinal

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Household participation in SILC by Income Quintiles in previous year

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1 2 3 4 50.0

0.5

1.0

1.5

2.0

Income Quintiles

% N

on-R

espo

nse

/ % R

espo

nse

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.

Thanks for listeing!

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