22 November 2010

The EU - Statistics on Income and Living Condition (EU-SILC) is a multi-purpose survey with the income and social inclusion as a core. It contains a small module on the health, including 3 questions on the general health status and 4 questions on the unmet needs of the health care.

The questions on the general health status represent the so called Minimum European Health Module (MEHM) and are proposed to be used in any EU health survey or survey module, in order to link results among surveys. These 3 questions are: self-perceived health, chronic (longstanding) illnesses or conditions and limitation in activities due to health problems.

The data on self-perceived health refer to the auto-evaluation of the general health state (i.e. any temporary health problem is not considered) by respondents using a scale from "very good" to "very bad". The indicator is one of the Open Method of Coordination on Social Inclusion and Social Protection (OMC), listed in its 1st objective.

The data on chronic (longstanding) illnesses or conditions refer to the self-declaration by the respondents of whether they have or have not a chronic (longstanding) illness or condition.

The data on limitation in activities (so called GALI question) due to health problems refer to the auto-evaluation by the respondents of the extent of which they are limited in activities people usually do because of health problems for at least the last 6 months (strongly limited = severe, limited = some, not limited = none). The indicator is one of the Open Method of Coordination on Social Inclusion and Social Protection, listed also in its 1st objective.

The variables of interest, apart from country, age and gender, are PH010, PH020, PH030; PE040, EQ_INC, ACTSTA from the EU-SILC cross-sectional database.

Data are used to produce various indicators. They are regularly disseminated under the 'public health' section of the Eurostat database in the following folders and subfolders:

• Health status: indicators from survey (SILC, HIS, LFS).
• Sub-folder: Health status: indicators from the SILC survey (from 2004 onwards).

Data are presented in the breakdown by:

    - sex, agegroup (9-years intervals from 16 years old and over) and activity status;

    - sex, agegroup (9-years intervals from 16 years old and over) and educational level;

    - sex, agegroup (18-44, 45-54, 55-64, 65-74 and more then 75) and income quintile.

• Health care: indicators from surveys (SILC, HIS round 2004)
• Sub-folder: Health care: indicators from the SILC survey (from 2004 onwards)

The indicators of unmet needs for medical and dental care are also part of OMC indicators.

Data are presented in the breakdown by sex, agegroup (18-44, 45-54, 55-64, 65-74 and  more then 75) and income quintile.

Finally but firstly presented in our dedicated section is the structural indicator Healthy Life Years (HLY). The indicator is calculated by combining mortality data with the GALI question. HLYE is a Sustainable Development Indicator as well as an OMC indicator.

EU-SILC is now implemented in 33 countries but was launched at different times:　

• 2003: BE, DK, EL, IE, LU, AT, NO
• 2004: EE, ES, FR, IT, PT, FI, SE, IS
• 2005: CZ, DE, CY, LV, LT, HU, MT, NL, PL, SI, SK, UK
• 2006: BG, TR
• 2007: CH, RO
• 2010: HR

The EU-SILC results are produced in accordance with the relevant international classification systems. The main classifications used are: ISCED 1997 for the level of education, occupation (ISCO 88 (COM) and ISCO 08 from 2011) and NACE (Rev.1.1 and Rev. 2 from 2008) for economic activity.

Not applicable

Age, Agegroup: the age at the time of the interview.

Educational level: under SILC, the attainment levels of individuals are classified according to the 'International Standard Classification of Education' version of 1997:

• Level 0: Pre-primary education
• Level 1: Primary education or first stage of basic education
• Level 2: Lower secondary or second stage of basic education
• Level 3: Upper secondary education
• Level 4: Post-secondary non-tertiary education
• Level 5: First stage of tertiary education
• Level 6: Second stage of tertiary education

The ISCED-97 classification is available on Eurostat's classification webpage.

Activity status: in EU-SILC, the activity status is a derivated variable and is defined as the main activity status during the income reference period (usually in (N-1)). For the health indicators are used 4 following categories: 

• POP: Population
• EMP: Employed persons
• UNE: Unemployed persons
• RET: Retired persons
• INAC_OTH: Other inactive persons

Income quintile: is computed on the basis of the total equivalised disposable income of year (N-1), i.e. total disposable household income divided by the household equivalised size using the so-called modified OECD equivalence scale. This scale gives a weight of 1.0 to the first adult, 0.5 to any other household member aged 14 and over and 0.3 to each child below age 14.

Self-perceived health: proportion of persons who assess their own health as being very good/ good/ fair/ bad/ very bad

Chronic (longstanding) illness or condition: proportion of persons who suffer from a chronic (longstanding) illness or condition

Limitation in activities due to health problems: proportion of persons who are strongly limited/ limited/ not limited in activities people usually do because of a health problem, in the past 6 months (strongly limited, limited, not limited).

For further details on the concepts of self-perceived health, suffering from any chronic (long-standing) illness or condition and limitation in activities because of health problems, please refer to the description of the SILC variables on health status (See annex at the bottom of the page).

Individuals aged 16 years old and over living in private households.

All individuals aged 16 years old and over living in private households. Persons living in collective households and in institutions are generally excluded from the target population.

• Countries: EU- Member States, Iceland, Norway, Switzerland, Turkey and Croatia.
• Aggregates:  EU-25 for 2005 and 2006; EU-27 from 2007.

2003: 6 EU Member states (BE, DK, EL, IE, LU, AT) plus NO.

2004: 13 EU Member states (BE, DK, EL, IE, LU, AT, EE, ES, FR, IT, PT, FI, SE) plus NO and IS.

2005 and 2006: EU-25 Member States plus NO and IS.

From 2007: EU-27 Member States, NO, IS, TR, CH, HR.

Not applicable.

Most indicators are reported as rates.  

The reference period for the three health status questions and for the demographic and educational characteristics is the current situation.

For the activity status and the income quintiles, the reference period is the income reference period (generally year (N-1).

EU-SILC is conducted in accordance with EU regulations:

• The Framework Regulations (regulation CE 1177/2003 of European parliament and Council adopted on 16 June 2003 and published in the OJ on 3 July 2003
• Regulation CE 1553/2005 of EP and Council adopted on 7 September 2005 and published in the OJ on 30 September 2005
• Council Regulation (EC) No 1791/2006 of 20 November 2006 as regards the accession of Bulgaria and Romania published in the OJ of 20 December 2006
• Regulation CE 1980/2003 on definitions published in the OJ on 21 October 2003
• Regulation CE 1981/2003 on fieldwork aspect and imputation procedures published in the OJ on 21 October 2003
• Regulation CE 1982/2003 on sampling and tracing rules published in the OJ on 21 October 2003
• Regulation CE 1983/2003 on the list of target primary variables published in the OJ on 7 November 2003
• Regulation CE 16/2004 on the content of intermediate and final quality reports published in the OJ on 6 January 2004
• Regulation on Community statistics on public health and health and safety at work (EC) No 1338/2008 on 16 December 2008.

For more details please refer to the ESMS pages of Community Statistics on Income and Living Conditions (EU-SILC) (follow the link at the bottom of this page).

Not available.

Regulation (EC) No 223/2009 on European statistics (recital 24 and Article 20(4)) of 11 March 2009 (OJ L 87, p. 164), stipulates the need to establish common principles and guidelines ensuring the confidentiality of data used for the production of European statistics and the access to those confidential data with due account for technical developments and the requirements of users in a democratic society.

For the dissemination purposes the following ruleas are applied:

An estimate should not be published if it is based on fewer than 20 sample observations or if the non-response for the item concerned exceeds 50%.

• An estimate should be published with a flag if it is based on 20 to 49 sample observations or if non-response for the item concerned exceeds 20% and is lower or equal to 50%.
• An estimate shall be published in the normal way when based on 50 or more sample observations and the item's non-response does not exceed 20%.

EU-SILC micro data does not contain any administrative information such as names or addresses that would allow direct identification. .

In order to ensure disclosure control and confidentiality of EU-SILC micro data access, some variables collected were removed or changed. On the other hand, in order to ease the use of the data, some variables were added. For more details see: 

 http://forum.europa.eu.int/Public/irc/dsis/eusilc/library?l=/data_dissemination/udb_user_database&vm=detailed&sb=Title

There is no release calendar.

Not applicable.

In line with the Community legal framework and the European Statistics Code of Practice Eurostat disseminates European statistics on Eurostat's website (see item 10 - 'Dissemination format') respecting professional independence and in an objective, professional and transparent manner in which all users are treated equitably. The detailed arrangements are governed by the Eurostat protocol on impartial access to Eurostat data for users.

Annual.

News releases on-line.

• SILC Health Status data are included in the Eurostat Yearbook.
• Statistics in Focus (SiF) number 24/2009 on the 'Perception of health and access to health care in the EU-25 in 2007' .

PDF versions are available on-line. 

Please consult free data on-line or refer to §1 Contact.

Due to the confidential character of the EU-SILC microdata, direct access to the anonymised data is only provided by means of research contracts. Access is in principle restricted to universities, research institutes, national statistical institutes, central banks inside the EU, as well as to the European Central Bank. Individuals cannot be granted direct access. Contact point: estat-microdataaccess@ec.europa.eu

Microdata release:

• cross-sectional data 01/03/N+2 (N= year of data collection)

longitudinal data 01/08/N+2

Internet address: http://ec.europa.eu/eurostat.

European health interview survey (EHIS) - 1st round 2007-2008 - background and rationale of the questions.

Reports on the health EU-SILC questiosn produced by EHLEIS (European Health & Life Expectancy information systems):

• Assessment of the GALI question used in SILC since 2008
• EU-SILC health questions 2004-2009 in national languages and back translations to English by the country experts 
• Health questions from the Minimum European Health Module used in EU-SILC in the 27 EU countries

For any other details see also the user SILC database description at Circa, as well as the ESMS pages of Community Statistics on Income and Living Conditions (EU-SILC) (follow the link at the bottom of this page).

See the annex on comparability issues between countries at the bottom of the page.

The EU-SILC regulations specified quality criteria are applied.

Output standardisation is achieved by defining the format (list and content of target variables, data format) and the timetable of data transmission. This is complemented by Eurostat consistency, integrity checks on the micro data so that minimum output quality standard is reached. The access to the EU database is also ruled by Regulation so that accessibility of output for researchers is guaranteed. In addition, countries should report to Eurostat on any deviation from the standard.

Data are accompanied with quality reports analysing the accuracy, coherence and comparability of the data. National and EU quality reports can be consulted on-line: http://circa.europa.eu/Public/irc/dsis/eusilc/library?l=/quality_assessment&vm=detailed&sb=Title.

The main users of the SILC data on health status are:

• Institutional users like other Commission services, particularly DG SANCO and DG EMPL for their needs in relation to the OMC and ECHI indicators as well as national administrations (mainly those in charge of the monitoring of public health, or other international organisations;
• Statistical users in Eurostat or in Member States National Statistical Institutes to feed sectoral or transversal publications such as the Annual Progress Report on the Lisbon Strategy (structural indicators), the Sustainable Development Strategy monitoring report, the Eurostat yearbook and various pocketbooks, among other reports;
• Researchers having access to microdata; and

End users - including the media - interested in public health in the EU.

Not applicable.

The geographical coverage of EU-SILC by year is the following:

• 2003: 6 EU Member states (BE, DK, EL, IE, LU, AT) plus NO
• 2004: 13 EU Member states (BE, DK, EL, IE, LU, AT, EE, ES, FR, IT, PT, FI, SE) plus NO and IS
• 2005 and 2006: EU-25 Member States plus NO and IS
• From 2007: EU-27 Member States, NO, IS, TR, CH, HR.

EU-SILC covers only people living in private households (all persons aged 16 and over within the household are eligible for the operation), i.e. persons living in collective households and in institutions are generally excluded from the target population. 

EU-SILC may also exclude small parts of the national territory amounting to no more than 2% of the national population and the national territories. National territories that may be excluded include the French Overseas Departments and territories, the Dutch West Frisian Islands, with the exception of Texel, the all Irish offshore islands with the exception of Achill, Bull, Cruit, Gorumna, Inishnee, Lettermore, Lettermullan and Valentia, and finally the Scotland north of the Caledonian Canal, the Scilly Islands.

According to the Regulation 1982/2003 on sampling and tracing rules, for all components of EU-SILC (whether survey or register based), the cross-sectional and longitudinal (initial sample) data are to be based on a nationally representative probability sample of the population residing in private households within the country, irrespective of language, nationality or legal residence status. The sampling frame and methods of sample selection should ensure that every individual and household in the target population is assigned a known and non-zero probability of selection.

Regulation 1177/2003 defines the minimum effective sample sizes to be achieved, i.e. the actual sample sizes will have to be larger to the extent that the design effect exceeds 1.0 and to compensate for all kinds of non-response. Furthermore, the sample size refers to the number of valid households which are households for which, and for all members of which, all or nearly all the required information has been obtained. The allocation of the effective sample size is done according to the size of the country and ensuring minimum precision criteria for the key indicator at national level (absolute precision of the at-risk-of-poverty rate of 1%).

Standard errors of key indicators are commonly used as a measure of the reliability of data collected through sample survey. EU-SILC was designed to provide measure of at-risk-of-poverty rate with an absolute precision of about one point. The sample sizes were defined taking into account this accuracy requirement. Member States compute variance estimates for the main indicators; Linearisation, Jacknife and Bootstrap techniques are programmed.

For further information please consult the national and EU quality reports: http://circa.europa.eu/Public/irc/dsis/eusilc/library?l=/quality_assessment&vm=detailed&sb=Title

The term 'non-sampling error' is a generic one that encompasses any errors other than sampling errors. The non-sampling errors discussed in this section are: coverage errors, measurement and processing errors, and non-response errors.

Coverage errors

Coverage errors are caused by the imperfections of a sampling frame for the target population of the survey.

In EU-SILC two main groups can be defined in terms of the sampling source used:

• Some countries have relied on household information from population registers. In order to make the best coverage of the target population, registers have to be updated frequently. It means any modification in the population (both people moving in and people moving out) must be reported as quickly as possible.
• Other countries have used Census databases in order to select addresses. The databases also have to be updated to represent the units that have come into being after the Census and thus ensure the cross-sectional representativeness of the sample.

A systematic source of coverage problems is the time lag between the reference date for the selection of the sample and the fieldwork period, which should be made the shortest. 

In addition, some countries carried out EU-SILC as a sub-sample of the units (addresses) that successfully cooperated to other existing surveys. Assuming selective non-response in these surveys, this may entail selection bias (under-coverage).

Measurement and processing errors

Generally, measurement errors arise from the questionnaire, the interviewer, the interviewee and the data collection method used.

It is vital in a survey like EU-SILC, which collects a multitude of complex income components, that the questionnaire is constructed so that the interviewee can provide as quickly as possible all the correct information. It appears that most of the countries took care in designing the questionnaire. In particular, experiences from pilot surveys and/or former EU-SILC waves were used in order to optimize the data collection process. The questionnaires were also tested in order to identify potential sources of problems. 

Due to the complexity and the sensitivity of the survey, the interviewees could not or did not want to give information about all their incomes. For instance, capital of self-employment income may have been under-reported. Besides, EU-SILC collects non-monetary income components (imputed rent, income from private use of company car...) that could have an unfamiliar terminology to some people. The risk of confusion on the information to report is then higher than with more conventional monetary income components.

Non-response errors

All surveys have to deal with non-response, i.e. information missing for some of the sample units. Unit non-response happens when no interview can be obtained, while item non-response does when only some of the items are missing. EU-SILC suffers from these two types of non-response:

• Unit non-response: when a household refuses to cooperate or is away during the fieldwork period. Other reasons can explain unit non-response: the questionnaire is lost; the household is unable to respond because of incapacity or illness... It may also happen that a person in a household refuses to cooperate although the household interview has been accepted ('individual' non-response).
• Item non-response: typically happens to questions the interviewee does not answer because he considers them personal or not easily understandable.

Non-response is a potential source of bias particularly if the non-responding units have specific survey patterns ('non-ignorable' non-response). For instance, one might expect persons with high incomes to be more reluctant to give income information to an interviewer, thus making the upper income class under-represented in the sample and the estimates downwardly biased. 

The Commission Regulation 28/2004 has defined indicators aiming at measuring unit non-response in EU-SILC: Address contact rate (Ra), Household response rate (Rh), Individual response rate (Rp). 

At this step, elaborate models controlling many external control variables are desirable in order to correct non-response. Most of the countries did apply either a standard post-stratification based on homogeneous response groups or a more sophisticated logistic regression model. 

Individual non-response rate appears to be marginal. Most of the countries have actually imputed missing individual questionnaires. 

Item non-response is high for some income components. It has been dealt with by imputation. The technique aims at 'filling the holes' in a distribution, so only unit non-response can be assumed. However, it has to be kept in mind imputed values are not exact values and underlain on a model that could not be the perfect fit of the reality. 

Imputation can have a significant effect on the overall accuracy: it generally skews a sample distribution so estimates will be biased. Furthermore, variance estimates assuming that imputed values are exact ones will be generally biased. The impact of imputation on the EU-SILC data is difficult to assess as yet. 

Total non-response of selected household/individuals is required to be below 40%.

Item non-response for non income variable is limited to 5%. When non-response in income components affects a subcomponent collected through interview, statistical imputation or modelling is required. This aspect is controlled in the datasets through imputation flags which represent the proportion of collected over recorded amounts.

Results from EU-SILC should be supplied by participant countries to Eurostat within 12 months of the end of the survey year, i.e. annual data for year N will be available in December of year N+1. The corresponding health status data are released on the Eurostat website in the first half of January N+2.

Not applicable.

To ensure comparability of data and/or indicators, i.e. to ensure quality of data as defined by Eurostat, EU-SILC has opted for an ex-ante output harmonization strategy.

When using output harmonization it is the goal that is determined, survey design and methods are flexible as long as the output requirements are met. Countries have to define suitable national concepts and measurement procedures with which the international concept can be portrayed. There are two different strategies depending on when the survey design is planned: with ex-ante harmonization, the surveys are created by the countries having in mind the output to produce; with ex-post harmonization, countries can adapt surveys already in place to produce comparable outcomes.

EU-SILC is based on a common framework defined by harmonized lists of target primary and secondary variables, common concepts, a recommended design, common requirements (for imputation, weighting, sampling errors calculation) and classifications aiming at maximising comparability of the information produced.

To anchor EU-SILC in the National Statistical System, survey design is flexible. The framework can be seen as a trade off in terms of standardisation of surveys leading to a good degree of comparability and flexibility allowing country's specificities to be taken into account in order to maximise quality of data. Eurostat and Member States work together to develop common guidelines and procedures aimed at maximising comparability.

The EU-SILC common framework aims ensuring standardisation at different levels.

1) Conceptual standardisation is achieved because the common concepts/definitions underlying each measure/variable, the scope and time reference are defined and documented.

2) Implementation and process standardisation is achieved by editing recommendations about collection unit to be considered, sample size to be achieved for each country, a recommended design for implementing EU-SILC (the so called 4-year rotational panel which almost all countries are using), common requirements for sampling and tracing rules for the longitudinal components, common requirement for imputation and weighting procedures. International classifications aiming at maximising comparability of the information produced are also enforced. Specific fieldwork aspects are also controlled by the framework: to limit the use of proxy interviews; to limit the use of controlled substitutions, to limit the interval between the end of the income reference period and the time of the interview, to limit to the extent for the total fieldwork of one-shot surveys, to define precise follow up rules of individuals and households in case of refusals, non-contact...

3) For the health status component of EU-SILC, a data translation protocol has been elaborated in order to check data comparability in all languages.

EU-SILC flexibility is a key aspect allowing for adaptation to national specificities in terms of infrastructure and measurement.  The most important element of the flexibility is related to the data sources (administrative or interview) to be used. Eurostat encouraged the use of existing ones, whether they are surveys or registers. A second aspect of the flexibility is related to the survey and sampling design. The only constrain is that, for both, the cross-sectional and longitudinal components, all household and personal data have to be linkable at micro level. Countries can use survey vehicles already in place, set up a new survey possibly drawing on one recommended by Eurostat. Sampling design can draw on expertise for social survey at national level. The third element of flexibility relates to the measure of self-employment income for which the diversity of the source and practice did not allow to find common harmonised solutions.

From 2007 onwards, Finland changed the question of the self perceived health and now it corresponds to the standard version of Questionnaire.

Limitation in activities due to health problems ("GALI question"):

1. Countries whose question was identical over the time period 2004-8: Austria, Belgium, France, Ireland, Luxembourg, Malta , Romania and Slovenia

2. Countries with changes in question between 2004-8 (question is now correct): Cyprus (change 2006); Czech Republic (slight change 2007 and 2008); Denmark (change 2008); Estonia (change 2006 and 2008); Italy (slight change 2005 and 2007); Latvia (slight change 2006); Poland (slight change 2006); Slovakia (change 2006 and 2008)

Spain (change 2008)

3. Countries with changes in question over 2004-8 (question still incorrect): Hungary (slight change 2007, more 2008 - duration 6 months rather than 'at least 6 months'); Netherlands (change 2008 - no duration of at least 6 months specified); Portugal (change 2005 and 2008 - daily activities not activities people usually so)

4. Countries with changes to question in 2004-8 (but unknown whether now correct or not): Finland (change 2007 and 2008); Germany (change 2006 and 2008); Greece (slight change 2007); Lithuania (change 2006 and 2007); UK (no change 2004-7 but form of 2008 question unknown).

5. In 2010 the GALI question was modified in Italy, Romania and Slovenia.

EU-SILC follows international standards: ISCO, NACE, ISCED, degree of urbanisation, Canberra recommendations for income data.

The sets of weights available in EU-SILC datasets have been obtained using calibration techniques which ensure basic coherence of estimates obtained from EU-SILC micro datasets and demographic counts.

Further coherence analysis with the European Health Interview Survey which includes exactly the same three questions of the MEHM is currently being implemented.

Not available.

EU-SILC was designed to keep respondent burden controlled so to avoid to high non-response rate and to ensure good quality of the information collected. The target is to limit the total length of interviewing household in average below 60 minutes. Significant decrease of interview duration is observed in countries using administrative data.

See the ESMS pages of Community Statistics on Income and Living Conditions (EU-SILC) (follow the link at the bottom of this page).

See the ESMS pages of Community Statistics on Income and Living Conditions (EU-SILC) (follow the link at the bottom of this page).

Data of Turkey are available only in 2006 - 2007.

For any other details about the processing and the source data, please follow the link at the bottom of this page to be transferred in the ESMS pages of Community Statistics on Income and Living Conditions (EU-SILC).

Annually.

See the ESMS pages of Community Statistics on Income and Living Conditions (EU-SILC) (follow the link at the bottom of this page).

For the indicators derived from EU-SILC the following rules apply:

":" no information available or the strata size is less than 20 or the item non-response is greater than 50%.

"u" low reliability because the strata size is between 20 and 49 or the item non-response is between 20 and49%.

(no flag) the strata size is greater than 50 and the item non-response is below 20%.

In these rules the concept of strata must be understood as the number of respondents belonging to the measured subgroup; for example the men in Belgium between 54 and 65 years old and having an ISCED level 6 for education.

Aggregate EU percentages are calculated as distributions throughout the whole sample of EU-SILC. 

See the ESMS pages of Community Statistics on Income and Living Conditions (EU-SILC) (follow the link at the bottom of this page).

The 3 health status questions composing the Minimum European Health Module (MEHM) are also used in the European Health Interview Survey (EHIS). The EHIS will be run every 5 years, the first time in 2008/2009 by most Member States. The MEHM will also be part of the probable future annual European Household Survey (EHS) which is planned from 2010 onwards in all EU-27 Member States.

The implementation of the health questions in SILC is not yet fully harmonized and, thus, the comparability of the results is to be further improved for some countries. New guidelines for this question were provided by Eurostat in October 2007 to the Member States, in order to improve the data comparability for the coming years.

Finland: the question on self-perceived health had for 2004-2006 answer categories which were not fully standard: "Good, Rather good, Average, Rather poor, Poor". In 2007 answer categories became standard and consequently figures are less comparable.

Other examples of problems related to the question on limitation in activities:

• the 6 months period is considered as a reference period and not as the minimum duration of the limitation
• the reference is to the respondent's own daily activities and not to the ones that people usually do
• the use of 2 answer categories instead of 3
• only persons who declare having a longstanding illness or health problem answer to this question instead of all persons irrespective of having or not a longstanding illness or health problem

For a more complete overview, please see the annex on comparability issues at the bottom of the page.