Statistics Belgium

Labour Market Statistics

North Gate
Koning Albert II-laan 16 

1000 Brussels

The Structure of Earnings Survey (SES) is a 4-yearly survey which provides EU-wide harmonised structural data on gross earnings and hours paid which are collected under Council Regulation (EC) No 530/1999 concerning structural statistics on earnings and on labour costs, and Commission Regulation (EC) No 1738/2005 amending Regulation (EC) No 1916/2000 as regards the definition and transmission of information on the structure of earnings.

The following classifications are used:

- NACE Rev. 2 for the economic activity;

- ISCO-08 for the occupation of the worker;

- ISCED11 for the highest successfully completed level of education and training;

- NUTS for the regional breakdown.

The Belgian SES refers to local units belonging to enterprises with at least 10 employees in the areas of economic activities defined by NACE Rev. 2 sections B to S excluding O.

Employees are all persons who have a direct employment contract with the enterprise or local unit and receive remuneration, irrespective of the type of work performed, the number of hours worked (full or part-time) and the duration of the contract (fixed or indefinite).

Mean annual gross earnings also cover all 'non-standard payments', i.e. payments not occurring in each pay period, such as: 13th or 14th month payments, holiday bonuses, quarterly or annual company bonuses and annual payments in kind.

Mean monthly gross earnings in the reference month cover remuneration in cash paid before any tax deductions and social security contributions payable by wage earners and retained by the employer, and are restricted to gross earnings which are paid in each pay period during the reference month.

Mean hourly gross earnings are defined as gross earnings in the reference month divided by the number of hours paid during the same period.

Number of hours paid includes all normal and overtime hours worked and remunerated by the employer during the reference month. Hours not worked but nevertheless paid are counted as 'paid hours' (e.g. for annual leave, public holidays, paid sick leave, paid vocational training, paid special leave, etc.).

The SES covers all activities defined in NACE Rev. 2 sections B to S (excluding O) for local units that belong to enterprises with at least 10 employees.

The SES refers to local units belonging to enterprises with at least 10 employees in the areas of economic activities defined by NACE Rev. 2 sections B to S excluding O.

The SES refers to local units belonging to enterprises with at least 10 employees in the areas of economic activities defined by NACE Rev. 2 sections B to S excluding O.

Reference year = 2014;

Reference month = October

Not applicable.

The Belgian SES makes use of three different administrative sources:

• The national register of enterprises (DBRIS)
• The earnings and working hours database of the National Office for Social Security (ONSS)
• The national register of individuals (RN)

A tailor-made questionnaire (NSI) is still necessary for obtaining the information that isn't available in existing datasets. The table below gives an overview of the different Eurostat variables and the way Statistics Belgium obtained them:

The Belgian SES is organised on an annual basis.

The SES 2014 was conducted based on a two-stage sampling approach. In the first stage, a stratified random sample of local units was drawn. The stratification criteria were the economic activity, the number of employees and the region of the local unit. The questionnaire, the explanation and a list of local units for which the survey needed to be filled in were sent to the head offices of the selected local units. We chose not to send the questionnaire to every local unit in the sample, since a central pay-roll administration is usually responsible for the payment of all wages. The possibility of a mistake by the enterprise, for example by taking the wrong local unit, is very limited, because every local unit in Belgium has its own unique administrative number. The continuously updated business register was used to define the sampling frame.

The chances of selection largely depended on the number of employees a local unit has. In the second stage, the local unit had to select a number of employees according to the instructions in the explanation. Local units with fewer than 300 employees had to select a proportion of their total number of workers:

Number of selected wage earners for local units with fewer than 300 employees 

Local units with 300 employees or more needed to select a fixed absolute number of workers:

Number of selected wage earners for local units with at least 300 employees

To ensure that the sample was drawn on a coincidental basis, every local unit received a letter of the alphabet. The local unit had to start its selection of employees with the wage earner whose surname began with that letter. If the number of wage earners was not reached at the letter ‘Z’, the selection continued with the letter ‘A’. No stratification criteria were used in this second stage, because we wanted to keep this step as easy as possible for the respondents.

Data validation consists of global checks and plausibility checks. Global checks are necessary to ensure that complete data are available. Plausibility checks on all variables were done to ensure that the data are reasonable and consistent with other variables.

Not applicable

Not applicable

Before transmission to Eurostat, the results of the SES are checked internally by the validation team. Also Eurostat validates the results by using several global checks and plausibility checks. Finally the Quality Report contains all relevant information to enable the quality of the statistic to be evaluated.

SES microdata are checked for completeness and consistency.

The results and data of the Structure of Earnings Survey (SES) are often used by the Belgian general public. Students, research centres, universities, trade unions, the media, private companies and public administration institutions can all be considered as important users of the SES.

One reason for this interest from a wide range of users comes from the large survey sample. Because of these large numbers, the SES can give a correct image of the gross earnings by several independent variables. Together with the Labour Force Survey, the SES is for example the only national source where earnings can be linked with important personal characteristics such as the level of education or the occupation of the worker. The rather unique combination between individual features on the one hand and enterprise characteristics on the other hand can also explain the broad use of the SES.

Although almost all demands can be met by the existing information and variables, there is still much interest in more personal characteristics of the workers. Aspects such as nationality or household situation of the worker often influence the earnings and labour time. Also in the framework of the gender pay gap this information would be very useful.

Not applicable.

Not applicable.

The SES 2014 was conducted based on a two-stage sampling approach. In the first stage, a stratified random sample of local units was drawn. The stratification criteria were the economic activity, the number of employees and the region of the local unit. The questionnaire, the explanation and a list of local units for which the survey needed to be filled in were sent to the head offices of the selected local units. We chose not to send the questionnaire to every local unit in the sample, since a central pay-roll administration is usually responsible for the payment of all wages. The possibility of a mistake by the enterprise, for example by taking the wrong local unit, is very limited, because every local unit in Belgium has its own unique administrative number. The continuously updated business register was used to define the sampling frame.

The chances of selection largely depended on the number of employees a local unit has. In the second stage, the local unit had to select a number of employees according to the instructions in the explanation. Local units with fewer than 300 employees had to select a proportion of their total number of workers:

Number of selected wage earners for local units with fewer than 300 employees 

Local units with 300 employees or more needed to select a fixed absolute number of workers:

Number of selected wage earners for local units with at least 300 employees

To ensure that the sample was drawn on a coincidental basis, every local unit received a letter of the alphabet. The local unit had to start its selection of employees with the wage earner whose surname began with that letter. If the number of wage earners was not reached at the letter ‘Z’, the selection continued with the letter ‘A’. No stratification criteria were used in this second stage, because we wanted to keep this step as easy as possible for the respondents.

See 6.2.1. for more information concerning the sampling errors.

In general, the coefficients of variation are low, although there are several exceptions. Especially in the breakdowns with a limited number of workers, it is almost impossible to organise a survey in which these groups are measured correctly without being exhaustive. This problem appears in several NACE-sections, in the ISCO 1 and finally in the age groups under 20 and 60 years and over.

Please see the attached document for detailed figures on the Coefficients of variation.

See further for more details on the non-sampling errors.

There were no differences between the reference and the study population. The universe and the sample survey were drawn up from the most recent business register available at the time. This register gives an overview of all enterprises and local units that had wage earners in service on 30 September 2014. Under or over coverage was therefore possible but would have a very limited impact, as only those local units who started or ceased their activities during the month of October could be affected.

With regard to the size of the enterprise Belgium chose to exclude the small enterprises with fewer than ten employees. We also excluded the NACE section O in our sample. This means that the Belgian datasets only include the local units covered by the Regulation.

Not applicable

Not applicable

In order to detect outliers and other quality problems, several aggregated checks were integrated into the different data collection tools. More complicated inconsistency problems were solved internally or by contacting the local unit on a bilateral basis.

The unit response rate for the entire survey amounts to 71%. The table below gives an overview of the response rates by economic activity: 

See 6.3.3 for more information

See 6.3.3. for more information

See further for more details.

Item imputation rate

Data completeness is one of the advantages of an administrative register. Consequently, for those variables of which the information is derived from existing datasets, the item imputation rates equals to 0 %.

For the variables included in the questionnaire, the item imputation rate is highest for the level of education. For 15.402 workers or 11.0 % of the cases, this information was imputed. Enterprises often inform us about the difficulties to obtain this specific piece of information. In general, the level of education is less relevant for enterprises, since their workers can compensate a lower degree of education by experience or other skills. This information therefore often remains uncentralised.

The occupation of the worker is the other variable with an high item imputation rate. For all the other variables the item imputation rates are less than 0.2 %.

Overall imputation rate

Given the very low item imputation rates, the overall rate is also negligible. Here all the information at the level of the local unit is derived from administrative datasets, the overall imputation rate for Record A equals to 0 %. Also for Record B this imputation rate is limited to 0.9 %.

No assumptions are made.

No seasonal adjustment takes place.

SES data aren't revised.

SES data aren't revised.

SES data aren't revised.

The two records with the thoroughly checked and internally approved data were sent to Eurostat on 28 June 2016. The data delivery took place before the deadline stipulated by the Regulation.

The two records with the thoroughly checked and internally approved data were sent to Eurostat on 28 June 2016. The data delivery took place before the deadline stipulated by the Regulation.

The two records with the thoroughly checked and internally approved data were sent to Eurostat on 28 June 2016. The data delivery took place before the deadline stipulated by the Regulation.

The field work started by sending the questionnaires on January 2015. At first the respondents/ enterprises had time until the end of February to fill in the questionnaire. Respondents who did not answer within this deadline received a first reminder early March and a second in April.

More intensive contact attempts were held in May and June. They aimed at convincing respondents to participate and at increasing the unit response rate. For the most important local units phone contacts were replaced with a visit. An employee of Statistics Belgium could then help respondents fill in the questionnaire when this was necessary. The field work was closed in September 2015, i.e. eight
months after the start.

Data processing started as soon as the questionnaires were sent to the respondents. For the overall quality of the data, we aim to check the received data as soon as possible. This allows us to contact the respondent within an acceptable time span when errors or missing items are detected.

Besides the survey data, some administrative sources were used to calculate the Eurostat variables. Even if these sources have several advantages, such as the correctness and the completeness of the data, they also have an important disadvantage: some of them were not received before spring 2016.

The final results of the SES 2014 were published in July 2016.

See general point 7.2.

Belgium has strictly followed the content of the Regulation. Geographical comparability should therefore be ensured.

A remark for education professionals is nevertheless in place. In Belgium the contractual labour time of these professionals differs substantially from the effectively performed labour time. This group of employees works several non-paid hours per week preparing classes and correcting student exams. This rather limited number of hours paid influences the amount of the hourly earnings, so variable B32 is used as the denominator there. The hourly earnings for this specific group of employees are therefore rather high and could differ substantially from the earnings available for other countries.

Not applicable

The SES 2014 is completely comparable with the SES 2010, there the same method and data sources are used.

Compared with the SES 2006, the SES 2010 used another classification for the variables concerning the economic activity of the local unit and for the occupation of the worker. Because the economic activity is one of the three stratification criteria, this change in classification could influence the comparability of the results between these two reference years.

Additionally, the surveys starting from reference years 2006 differ from the SES 2002 in two ways:

1. In 2002, the main economic activity of the local unit was unknown. For this survey we worked with the assumption that the economic activity of the local unit was exactly the same as the activity of the enterprise to which it belonged. Since the SES 2006, this problem has been solved, so one enterprise could have local units executing different activities.
2. In 2002, the definition of a local unit did not correspond with the concept used by Eurostat. According to the Belgian definition, a company could never have more than one local unit with the same economic activity in one municipality. This meant that in 2002 a company was supposed to count up the wage earners of all its local units in every municipality. In the meantime, the Belgian definition of a local unit was adapted to the European rules. Since the SES 2006, it is therefore possible that one enterprise has several local units with the same activity in the same municipality.

See point 8.2.

The following table compares the survey’s variable “Gross annual earnings in the reference year” with the variable “wages and salaries” from the national accounts. Comparisons between these two sources should nevertheless be done carefully, because several differences concerning the target population and the followed methodology exist. The figures of the national accounts include for example businesses with fewer than ten employees, while these enterprises are excluded in the SES.

Given the above remarks, the figures are nevertheless comparable for the majority of economic activities:

Not applicable

See 8.3. for a comparison between National Accounts and the SES.

Not applicable

Every year, Statistics Belgium publishes a press release to explain and illustrate the main results of the SES. This communiqué is generally broadly covered by Belgian newspapers and news agencies.

In Belgium, the SES is organised on a yearly basis and is therefore well-known by the general public. Nevertheless, each year we use several channels to disseminate the SES results.

The results of the SES are also integrated in several publications. Some key results are included in the annual key figures published by Statistics Belgium. Also the annual Gender Pay Gap Report is worth mentioning. This elaborate publication describes the differences between men and women in the Belgian labour market. The SES is by far the most important source of this report.

The main channel to communicate the results is the dedicated section on the website of Statistics Belgium. This webpage contains the most popular aggregated tables, but visitors can also compose their own tables with our dynamic application. The earnings information is one of the most popular sections of the website, with more than 1,000 unique visitors every month.

See 9.3. for more information on this point.

Researchers can obtain microdata for their research project. On the website of Statistics Belgium, researchers can find more information on the procedure.  

The Belgian SES anonymised microdata are also accessible via CD-ROM by following the Eurostat procedure.

For users needing more detailed data, Statistics Belgium can produce tailor-made tables. 

The metadata are published on the website of Statistics Belgium.

The metadata are published on the website of Statistics Belgium.

100%

The metadata are published on the website of Statistics Belgium.

Statistics Belgium tries to reduce the burden for enterprises by using intensively administrative datasets. Yet a questionnaire is necessary to complete missing information. The cost for business to complete this questionnaire is measured yearly.

The Belgian confidentiality policy is followed. More information can be found on the website of Statistics Belgium.

The Belgian confidentiality policy is followed. More information can be found on the website of Statistics Belgium.

Not applicable