Persons interviewed (SILC)

SILC (Statistics on Income and Living Conditions) is a representative survey of households in Switzerland. The data collected enable a description to be made of the social and economic conditions of life in Switzerland and a better understanding of what influences them. Furthermore, they allow key statistics to be established on income distribution, the risk of poverty, material and social deprivation, life satisfaction, subjective assessment of the financial situation, debt, relationship with money (not available in English) and childcare (not available in English). The annual analyses serve as an important basis for decisions in the field of social politics.

The SILC survey is coordinated on a European basis in over 30 countries and is known as EU-SILC. This enables the Swiss results to be compared with those of other countries.

No, participation in this survey is not compulsory but we depend on it enormously. The results can only accurately describe the varied living conditions in Switzerland if a high proportion of the selected households respond to our questions. Social politics requires reliable data on income and living conditions in order to make informed decisions. Key statistics will be established on income distribution, the risk of poverty, material and social deprivation, life satisfaction, evaluation of the financial situation, debt, relationship with money (not available in English) and childcare (not available in English).

Households are randomly selected from the FSO's sample register. This register is primarily based on the official communal and cantonal population registers (see also "How did the FSO obtain my address?").

The questions are primarily related to incomes, housing costs and housing conditions, education, work, quality of life, childcare and health. As it is difficult to answer certain questions spontaneously, we advise you to get the following documents ready:

• Most recent tax declaration for all household members
• For tenants: Rental agreement
• Costs associated with your accommodation (e.g. water, electricity, gas, heating, apartment service charges, building insurance, regular costs for maintenance and repairs)

Since 1st November 2010, the FSO has used a sample register from which it obtains its survey samples. This frame is built from the data which must be provided by the communal and cantonal population registers as part of the new Federal Population Census system. The data are updated every trimester and include the basic data of all persons living in Switzerland.

According to Article 10, para. 3quater of the Federal Statistics Act (RS 431.01), all public telephone service providers active in the Swiss market are obliged to furnish to the FSO data about their customers which are necessary to conduct sample surveys. Consequently, the sample register currently used by the FSO comprises all fixed-line telephone numbers in Switzerland, regardless of whether they are listed in a telephone directory. Furthermore, mobile telephone numbers are also used if listed in a telephone directory.

The FSO is committed to upholding data protection provisions in its daily business. Personal data such as surname, address or telephone number are not stored together with the responses and are deleted as soon as the survey process is completed. Once the survey is concluded, the survey institute supplies the data to the FSO and is then contractually required to destroy them. The data are disseminated by the FSO so that they are completely anonymous. This makes it impossible to draw conclusions about individual persons or households. Staff at the FSO and the survey institute MIS Trend are bound to professional confidentiality.

The protection of data is guaranteed by the law on the Federal Statistics Act (RS 431.01), the Ordinance on Federal Statistics (SR 431.011), only available in German, French and Italian) as well as the Federal Act on Data Protection (RS 235.1).

Prior to being interviewed, each household selected to participate receives a letter from the FSO which explains the contents of the survey and how it will be conducted. The enclosed leaflet summarises the most important information. The letter contains a unique security code. At the beginning of the interview, the institute MIS Trend introduces itself and provides information about the survey which matches what was explained in the letter.

If you have any doubt about the caller's identity, you can ask the interviewer to say the security code to confirm their identity. Any persons who wish to ensure that they have indeed been selected for the survey may contact the SILC hotline (freephone number: 0800 001 008).

The volume of the FSO's surveys varies greatly from year to year and month to month. Private survey institutes are in a better position to spread the workload because they also conduct numerous other surveys.

The survey institute is chosen via a public tendering procedure (only available in German, French and Italian): the institutes are thoroughly evaluated and any collaboration with the FSO set out in a detailed contract. The institute must meet high professional, economic and technical requirements. Considerable emphasis is placed on training the institute's staff and monitoring their work on a continuous basis. In addition, the FSO provides intensive assistance for and monitoring of the execution of the survey contract.

The selected households are interviewed by telephone once a year over several consecutive years. In order to minimise the time required of participating households, the FSO makes use of information from several administrative sources to which it has access (see also "Why does the FSO use register information?").

The SILC survey targets all persons from the selected households aged 16 and over. The household questionnaire - which one person answers for the entire household - takes 10 to 15 minutes. The individual questionnaire - which is answered by all persons aged 16 or over - takes 25 to 30 minutes. You can find the current questionnaires here (available in French, German and Italian).

By following the same households over four years, a better analysis of the main phases in people’s life trajectories can be achieved. For example, a more precise analysis can be made of the impact on living conditions brought about by a change in one’s working life (e.g. labour market entry, change of job, retirement, etc.) or private life (e.g. birth, divorce, widowhood, etc.)

It is very important that you take part in the survey over several consecutive years even if there has been little change in your situation.

In addition to the basic questionnaire, one or more specific topics are addressed each year:

• 2007: Housing conditions
• 2008: Over indebtedness and financial exclusion
• 2009: Material deprivation
• 2010: Intra-household sharing of resources
• 2011: Intergenerational transmission of disadvantages
• 2012: Housing conditions
• 2013: Well-being / material deprivation / indebtedness / cultural participation
• 2014: Material deprivation
• 2015: Social and cultural participation / material deprivation / fortune
• 2016: Access to services
• 2017: Health and children's health / indebtedness
• 2018: Well-being / housing
• 2019: Intergenerational transmission of disadvantages
• 2020: Wealth / indebtedness / consumption / labour
• 2021: Children / Covid-19
• 2022: Health / quality of life (well-being and social and cultural participation)
• 2023: Energy efficiency / intergenerational transmission of disadvantages / housing difficulties
• 2024: Access to services / children
• 2025: Health
• 2026: Wealth / indebtedness / labour

The FSO is aware of the burden involved in responding to surveys for the Confederation. We make every effort to reduce this burden to a minimum without compromising our information mandate. Consequently, the Federal Council and Parliament have decided that information that is already available in the registers does not have to be provided in surveys (Federal Statistics Act of 9th October 1992, RS 431.01). Specific surveys are still necessary for all important information that is not available in the registers. For example, the SILC survey collects information on topics such as health, satisfaction, housing conditions, quality of life and childcare.

The following information is usually taken from registers and used for the SILC survey:

• Household contact information such as address and telephone number.
• Demographic information on the households selected such as sex, age, nationality and civil status.
• Information on certain income sub-components such as 1st pillar pensions (OASI), unemployment insurance and salaries subject to social insurance contributions.

SILC is a European survey that is coordinated by Eurostat. The information to be collected is specified in the European Commission's ordinances and in great detail in a reference document called "DocSILC065 Methodological guidelines and description of EU-SILC target variables". This makes it possible to compare results in over 30 European countries.

To satisfy the needs of other sections of the FSO or other federal bodies, some additional questions may be added to the European questions.

SILC is based on the legal bases of the Swiss Federal Statistical Office (FSO), which are regulated in the Federal Statistical Act and in the associated implementation Ordinance.

Legal underpinnings

The FSO carries out a random sample register to conduct household surveys. This draws mainly from official cantonal and communal population registers. In order to make contact, the sample was completed as much as possible with telephone numbers that must be provided to the FSO by telephone providers. This list contains all private telephone connections, including those that do not appear in the publicly available telephone directory.

Personal data such as name, address and telephone number are saved separately from answers and erased as soon as the survey process is over.

Legal underpinnings

Data are treated in a strictly confidential way and are used for statistical purposes only. Use of the information for commercial or administrative purposes is prohibited.

The results are published in a form which prevents identification of specific households or persons.

All employees of the FSO and MIS Trend have an obligation to maintain secrecy.

Further information (in German):

• Armut und Deprivation
• Einkommensverteilung
• Subjektives Wohlbefinden und Lebensbedingungen