The Structure of Earnings Survey is a four-yearly statistical operation (from the results of the 2002 Survey), carried out within the framework of the European Union with common criteria of methodology and contents, with the aim of obtaining comparable results on the structure and distribution of wages among its Member States. This survey investigates the distribution of wages according to a great variety of variables such as sex, occupation, branch of activity, seniority, or the size of the company.
Classification of the branches of economic activity: The National Classification of Economic Activities of 2009 (CNAE-09) is used at two digit level to classify the first stage units.
Occupation: Data are coded at 3-digit level of the National Classification of Occupations 2011 (CNO-2011).
Education (highest level of studies): The data are coded at two digit level of the National Classification of Education-2000, (NCED-2000) for the level of education until the reference period 2010 and following the National Classification of Education-2014, (NCED-2014) in this last edition.
As of 2010, the contribution centres of the General Social Security System have been included, whose economic activity is included in sections B to S of the CNAE-09 and in the Special Scheme for Seafarers and whose economic activity is Water transport (division 50 of CNAE-09).
The survey excludes agricultural, livestock and fishing activities; partially, Public Administration, Defence and compulsory Social Security (public employees belonging to the General Social Security System are included); domestic personnel and extraterritorial bodies.
The procedure of random selection of units corresponds to a two-stage stratified sample, where the first stage units are the Social Security contribution accounts, while the second stage units are the employees associated during the month of October with said contribution accounts.
The population scope is made up of all employed workers who provide their services in contribution centres, regardless of their size, and have been registered with the Social Security throughout the month of October of the reference year. It excludes presidents, members of boards of directors and, in general, all personnel whose remuneration is not mainly in the form of salary, but by commissions or benefits.
The geographical scope covers the entire national territory with results obtained by Autonomous Communities.
The Structure of Earnings Survey is a four-yearly statistical operation (from the results of the 2002 Survey). This survey has been carried out for the reference years 1995, 2002, 2006, 2010 and 2014.
The Structure of Earnings Survey has undergone several methodological changes due to the broadening of coverage in the fields of study as well as the implementation of new classifications for both activity and occupation. As a result of this, the homogeneous series begins in 2010 and covers the editions of 2010 and 2014, since it investigates the same areas and uses the National Classification of Activities CNAE-09 and the National Classification of Occupations CNO-11.
Euros per employee per year
Euros per hour worked
There are two reference periods in the survey. Most of the questions refer to the month of October of the reference year. This month has the advantage of being considered "normal" in all EU countries, in the sense that it is little affected by seasonal variations or by payments that are due more than one month, such as Christmas payments. Other data refers to the year as a whole. In this way, monthly and annual earnings are obtained.
Data referring to the period: Structure of Earnings Survey 2014 final
The compilation and dissemination of the data are governed by the Statistical Law No. 12/1989 "Public Statistical Function" of May 9, 1989, and Law No. 4/1990 of June 29 on “National Budget of State for the year 1990" amended by Law No. 13/1996 "Fiscal, administrative and social measures" of December 30, 1996, makes compulsory all statistics included in the National Statistics Plan. The National Statistical Plan 2009-2012 was approved by the Royal Decree 1663/2008. It contains the statistics that must be developed in the four year period by the State General Administration's services or any other entity dependent on it. All statistics included in the National Statistics Plan are statistics for state purposes and are obligatory. The National Statistics Plan 2017-2020, approved by Royal Decree 410/2016, of 31 October, is the Plan currently implemented. This statistical operation has governmental purposes, and it is included in the National Statistics Plan 2017-2020. (Statistics of the State Administration).
The Structure of Earnings Survey is carried out within the framework of the European Union (EU) with common criteria of methodology and contents in order to obtain comparable results on the level, structure and distribution of wages among its Member States. For this reason, it uses the same reference period, scope of coverage, required information and characteristics of it, data collection method, representativeness, processing and transmission of results, in accordance with EU Regulations No. 530/1999 and No. 1738/2005, which are mandatory for all Member States.
More information about the reference regulations:
The INE provides information on the protection of confidentiality at all stages of the statistical process: the INE questionnaires for the operations of the National Statistical Plan include a legal clause that protects data by virtue of statistical secrecy. Notifications prior to data collection indicate respondents that the data will be subject to statistical confidentiality at all stages of the process.
For data processing, INE staff have available the INE Data Protection Manual, which specifies the steps to be taken at each stage of the process to ensure that the individual data of reporting units are protected. The manual is currently under study and its contents are being updated.
In statistical operations, direct identification data are not stored together with the statistical information itself after the data collection phase.
The microdata files provided to users are anonymised.
The results of the survey are disseminated every four years.
Users can access the data through the INE website. Specifically, there are the following links:
- Press release: contains a summary of the results obtained.
- Main results: document that describes, with tables and graphs, the main results obtained.
- Detailed results: where the different tables compiled are presented for each year that the survey is conducted.
In addition, there is information on the publications “Spain in Figures”, “Statistical Yearbook of Spain” and some monographic number of the collection INE Figures. These publications can be consulted on the INE website and downloaded in pdf format free of charge.
INEbase is the system the INE uses to store statistical information on the Internet. It contains all the information the INE produces in electronic formats. The primary organisation of the information follows the theme-based classification of the Inventory of Statistical Operations of the State General Administration . The basic unit of INEbase is the statistical operation, defined as the set of activities that lead to obtaining statistical results on a determined sector or subject based on the individually collected data. Also included in the scope of this definition are synthesis preparation.
Information can be obtained from the following link:
Public use files with non-identifiable microdata are available free of charge on the INE website. Users may also request anonymous data files with more detailed information under strict confidentiality conditions. See at https://www.ine.es/dyngs/INEbase/en/operacion.htm?c=Estadistica_C&cid=1254736177025&menu=resultados&secc=1254736195110&idp=1254735976596
There is the possibility of requesting tailor-made information from the INE User Service Area. These requests are processed taking into account limitations on confidentiality or accuracy.
A detailed description is available at:
The questionnaires for each year are available at:
The Quality Reports are prepared and sent to Eurostat, complying with Commission Regulation 698/2006, 24 months after the end of the survey reference year. The report for the survey with reference year 2014 will be available at the end of 2016.
This standardised methodological report contains, in fields 11 to 19, the elements of what it considers to be the "user-oriented quality report" for this operation.
Quality assurance framework for the INE statistics is based on the ESSCoP, the European Statistics Code of Practice made by EUROSTAT. The ESSCoP is made up of 16 principles, gathered in three areas: Institutional Environment, Processes and Products. Each principle is associated with some indicators which make possible to measure it. In order to evaluate quality, EUROSTAT provides different tools: the indicators mentioned above, Self-assessment based on the DESAP model, peer review, user satisfaction surveys and other proceedings for evaluation.
The statistics compilation process has established controls to detect and correct errors in order to guarantee the quality of the statistics from the beginning of the process. The phases of collection, recording and cleaning of information are fundamental stages in the development of any statistical research.
Before processing the information, an exhaustive control is carried out on the data provided by the reporting units to ensure their validity.
The data received undergoes a double control:
- A first simultaneous cleaning to the recording is carried out in the collection units, with the aim of detecting incomplete and erroneous questionnaires, as well as guaranteeing the coherence of the recorded data.
- A second control is carried out in the central services in order to avoid inconsistencies between related variables, which is combined with a macro-cleaning according to the elevated data obtained.
In any case, if any erroneous or inconsistent data is detected, the collection unit responsible for the questionnaire establishes telephone contact with the respondent to clarify the information.
In general terms, the cleaning focuses on the following aspects:
- Detect incomplete questionnaires: partial non-response is not allowed.
- Ensure data consistency: The data must respect the legal limits established in terms of working hours, minimum wages, etc. On the other hand, the questionnaire is divided into well-differentiated but closely interrelated blocks among which there must be some coherence. Thus, for example, overtime is not allowed without their payments, nor special situations without the period to which they refer, etc.
The Structure of Earnings Survey is a high quality product. Its sample size allows to provide indicators up to the regional level within reasonable sampling errors; the harmonised methodology used allows to offer comparisons at the international level with a high level of solvency and gives an extremely valuable measure on the distribution of wages in function of numerous characteristics of the employees.
Regarding the limitations of the survey, it is necessary to point out those inherent to sampling statistical operations, such as non-response and the aforementioned sampling errors or coefficients of variation of the estimates. In both cases, these are kept within reasonable limits.
The main users can be classified into the following groups:
- International Organisations: EU institutions, OECD, International Monetary Fund, International Labour Organisation, etc.
- Public bodies: Different ministries, such as the Ministry of Economy, the Ministry of Employment and Social Security, etc., and the National Statistics Institute for several of its units, such as national accounts, the Bank of Spain, regional institutions, etc.
- Social institutions such as trade unions, employers' organisations, political parties
- Research centres and universities
- The media
Each of these users has different needs according to the destination and usefulness of the information they require.
The INE has carried out general user satisfaction surveys in 2007, 2010, 2013 and 2016 and it plans to continue doing so every three years. The purpose of these surveys is to find out what users think about the quality of the information of the INE statistics and the extent to which their needs of information are covered. In addition, additional surveys are carried out in order to acknowledge better other fields such as dissemination of the information, quality of some publications...
On the INE website, in its section Methods and Projects / Quality and Code of Practice / INE quality management / User surveys are available surveys conducted to date.(Click next link)
In the user satisfaction survey carried out in 2013, which can be consulted on the INE website in its section on Quality-->Quality management-->Quality assessment and monitoring systems-->User surveys, you can see the assessment of the sector “Labour Market: Economically Active Population Survey, Labour Costs” in which this statistical operation is framed, which can guide the opinion of users about it.
In general, users are satisfied. However, they consider that the survey should have a larger sample size to provide a more detailed breakdown of some variables (in particular, geographical breakdown, economic activities and earnings components). They also request to include in the questionnaire more variables related to the employees being surveyed, such as their family situation, number of children, etc.
The Structure of Earnings Survey satisfies all the requirements established in national and international regulations related to structural statistics on wage earnings.
(R1): Rate of available mandatory statistical results=100%
The sample design tries to minimise sampling errors and the different processes of the survey are aimed at eliminating or reducing errors as far as possible, both in the collection phase (response rate and cleaning control) and in the subsequent editing and imputation phases.
The calculation of the coefficients of variation of the main variables is made in each survey implementation and are disseminated in its publication and in the quality reports. More information at:
During the entire statistical process, a control of non-sampling errors is carried out. Specific information on the non-response rate is also available.
The investigated population is formed by all the salaried employees who work for an employer during the month of October of the reference year of the survey. The framework used for sample selection is the General Register of Social Security Contribution Accounts of the Ministry of Labour and Social Security as at 30 September of the reference year. When it has been received from the Social Security, a first cleaning is made before the selection of the sample, which involves several stages:
- Eliminate economic activities that are not part of the survey: agricultural, livestock and fishing activities; households with domestic service and extraterritorial organisms.
- Eliminate the units that belong to the special Social Security system for commercial agents, whose main remuneration consists of commissions on sales and which, therefore, should not be surveyed.
After this, the sample is selected and the questionnaires are sent to the selected units; data collection and cleaning reveal errors in the surveyed units.
Errors in the framework:
For the year 2014:
The definitive sample size was 27,339 Social Security contribution accounts and 227,830 employees, distributed with optimal allocation according to the size stratum to which the contribution account belongs.
Of the 27,339 units selected, 26,534 were surveyable (25,087 surveyed and 1,447 refusals). The unsurveyable units were 805, out of which 722 were unreachable, 39 were closed or without activity and 44 were erroneously included or out of scope.
The response rate was 92% in both first and second stages.
Measurement and processing errors
In order to facilitate the response to the respondents, the information required has been approximated to the documents (payrolls, social contribution bulletins and annual summary of withholdings and payments on account of Personal Income Tax) that the employer must prepare in relation to their employees.
Cleaning of errors
A first cleaning is carried out, which consists in the use of filters referring to the errors that allow us to classify the valid questionnaires from those that have inconsistencies that must be corrected.
The filters are of two types called type I and type II.
Type I errors:
If they are not completely corrected, the questionnaire cannot be considered valid.
Type II errors:
They affect the standards that have to be met for data consistency. Non-compliance with these standards does not necessarily mean that the questionnaire is not valid, but it must be explained why it happens. In case of doubt, the respondent is contacted.
There are more than 200 rules that are checked for each employee. After the tabulation, the results obtained are analysed and combined with a macro-cleaning according to the elevated data obtained.
The provisional results of the survey referring to year t are published in t+18 months. The final results in t+22 months.
The results of the statistics are published according to the INE statistics availability calendar (https://www.ine.es/en/daco/daco41/calen_en.htm)
Each publication has been released on the date announced in the availability calendar.
The availability of a methodology, a design and a common process of collection, cleaning, edition and elevation in all its geographical scope, guarantees the comparability of the results between the different Autonomous Communities.
With regard to international comparability, the survey methodology follows the concepts and definitions of Council Regulation (EC) No. 530/1999 of 9 March 1999 concerning structural statistics on earnings and on labour costs, which allows for comparison between the different EU Member States.
The objectives, the variables and the methodology of the survey have been maintained in all of their conducts. However, its coverage has been extended on each occasion, so that temporal comparison is only possible if the same areas are analysed. It should also be borne in mind that over the years the classifications used have changed, which has repercussions on the comparability of the different activities or occupations according to the different classifications.
Thus, in the 1995 reference year, the contribution accounts of 10 and more employees in the economic activities included in sections C to K of CNAE-93 were investigated. In 2002, the activities investigated were extended to sections M to O of CNAE-93. In 2006, the contribution accounts from 1 to 9 employees were included and the same activities were maintained as in 2002. In 2010, public employees belonging to the General Social Security System of section O of CNAE-09 (Public Administrations, Defence and Compulsory Social Security) were included. The 1995, 2002 and 2006 surveys used the classifications of economic activities CNAE-93 and occupations NCO-94, but in 2010 and 2014 the classifications of economic activities CNAE-09 and occupations NCO-11 have been used.
CC1=2 considering all variables and classifications since 2010.
The use of the same national classification of economic activities and/or of occupations and/or of education allows the possibility of contrasting the information with other economic statistics on common variables.
The survey estimates have complete internal coherence, since they are based on the same corpus of microdata and are calculated using the same estimation methods. Arithmetic and accounting identities in the production of data sets are observed.
In order to facilitate the response to the respondents and reduce the informative burden as much as possible, in the survey referring to 2010 and 2014, those variables that can be obtained from the Social Security registers have been eliminated, such as sex, year of birth and nationality.
The estimated credit needed to finance this survey foreseen in the annual programmes from 2014 to 2016 amounts to a total of 2,006.04 thousand euros.
The INE of Spain has a policy which regulates the basic aspects of statistical data revision, seeking to ensure process transparency and product quality. This policy is laid out in the document approved by the INE board of directors on 13 March of 2015, which is available on the INE website, in the section "Methods and projects/Quality and Code of Practice/INE’s Quality management/INE’s Revision policy" (link).
This general policy sets the criteria that the different type of revisions should follow: routine revision- it is the case of statistics whose production process includes regular revisions-; more extensive revision- when methodological or basic reference source changes take place-; and exceptional revision- for instance, when an error appears in a published statistic-.
The INE has a Policy that regulates the basic aspects of the revision of the statistical data, guaranteeing the transparency of the processes and the quality of the products. This policy is described in the document approved by the Board of Directors at the meeting held on 13 March 2015. The document is available in the section “Quality and good practices” of the INE website.
This general policy sets out the criteria to be followed for the different types of revisions: routine revisions - in cases of statistics that by their nature are regularly revised; major revisions, due to methodological changes or changes in the basic sources of reference of the statistics; and extraordinary revisions (for example, those due to an error in statistics already published)
The provisional results are published simultaneously with the submission of the micro-data to Eurostat (in t+18 months). Eurostat monitors the micro-data so that they verify all the criteria established in the regulatory standards. Once this validation process is completed, the final results are generally published four months later.
As a consequence of the microdata validation process, in 2010 we have essentially revised the coding of the occupation, with no changes in the total figures.
For the year 2014, some variables have been revised such as the seniority and age of the employees but there has been no change in the total figures.
The starting point is the General Register of Social Security Contribution Accounts, sent by the General Treasury of Social Security and updated as at 31 October of each year, a framework that has the advantage of being continuously updated, in addition to the fact that its unit is the survey unit itself.
We obtain from the register the Directory of Social Security Contribution Accounts classified in the divisions of economic activities object of study, from which we extract the sample of contribution accounts.
The procedure of random selection of units corresponds to a two-stage stratified sample, where the first stage units are the Social Security contribution accounts, while the second stage units are the employees.
The first-stage units are classified by economic activity according to the national classification in effect, which are considered independent populations for sampling purposes. Each activity is stratified by Autonomous Community (18 in total, considering the group formed by Ceuta and Melilla) and by eight size intervals, being the units of 500 and more employees comprehensive.
The list of units selected in the first stage is sent back to the General Treasury of the Social Security who obtains the list of employees who were registered during the whole month of October of the reference year. From this list the employees are selected, the second stage units. In addition, from this register and for the selected employees, the following variables are obtained: sex, year of birth and nationality.
The final sample size was 27,339 Social Security contribution accounts and 227,830 employees in 2014, distributed with optimal allocation according to the size stratum to which the contribution account belongs. The final sample was 25,087 units and 209,436 employees.
The data collection has been carried out every four years since 2002.
The collection is carried out mainly via the Internet, but it is also possible to send the questionnaire by post mail or e-mail according to the choice of the respondent.
The phases of collection, recording and cleaning of the information are fundamental stages in the development of any statistical research. It is essential to carry out a strict control of the fulfilment of the various tasks associated with it.
Before processing the information, an exhaustive control is carried out on the data provided by the reporting units to ensure their validity. The data received undergo a double check:
- A first cleaning carried out by the collection units, simultaneous to the recording and coding of the questionnaires and whose purpose is to detect incomplete and erroneous questionnaires, as well as to guarantee the coherence of the recorded data.
- A second control carried out in the central services in order to avoid incongruities between related variables and that is combined with a macro-cleaning according to the elevated data obtained.
In any case, if any inconsistency is detected in the questionnaire, telephone contact is established with the respondent to clarify the information.
In general terms, the cleaning focuses on the following aspects:
- Detect incomplete questionnaires: There must be certain data from the questionnaire such as employees, agreed working hours, total earned, etc.
- Guarantee the consistency of the data: The data must respect the legal limits established in terms of working hours, minimum wages, etc. and certain coherence filters, so, for example, overtime hours are not allowed without their payments, nor special situations without the corresponding period, etc.
Once the validation process is completed, the elevated data are obtained. To do this, we use separate reason estimators, using as an auxiliary variable the number of employees in the Social Security Contribution Accounts Directory.
More information at:
No seasonal adjustments are made.