Collective labour agreement wages, indices (series 2010 = 100)

What does the survey comprise?

Research target

Quantification of the development of the contractual wage, labour costs and working hours of employees in the Netherlands.

Target Population

Employers in the Netherlands belonging to collective labour agreements (cao).

Statistical unit

Cao-wages of employers in the Netherlands.

Initial research

Started in 2010.



Official Strategy

The results are published in an index form, starting from 2010, that is set to 100. The monthly figures are published within one week after the relevant calendar month. This is called the first known published figure. Then each month the index is revised based on new concluded collective labour agreements.

There are two versions of the results: current figures and first-published figures.
Current figures are the most recent figures for the whole series starting from January 2010.
First-published figures are outdated. They are the first ever published figures for each reporting period and they will not be revised.
Current figures with * are provisional figures. This figure can be reviewed every month based on new collective labour agreements until the second quarter. In this month the figures of the previous calendar year become final (current figure without *).

Besides monthly figures also quarterly and annual figures are published. These figures are calculated as the average of the quarter or year. In addition also year-on-year changes are published.
Results in the contractual labour costs and the percentage of concluded collective agreements are published in less detail than the results on the collective wages and contractual working hours.

How is the survey carried out.

Survey type


Survey method

Collection of data on wages and working hours as listed in the concluded collective labour agreements (cao).
The index of contractual wage costs are based on collective wage amounts plus legal and contractual employer contributions for pensions, early retirement, unemployment, sickness, disability and social funds.


Companies, institutions and employers' organizations involved in concluding collective agreements.

Sample size

The Netherlands has approximately 1250 cao agreements. The indices of collective wages contain more than 225 collective agreements, including employment agreements that apply to the government. These are basically all major collective agreements (from 2500 workers) and a sample of smaller agreements. About 95 percent of all collective labour employees are directly represented by the results.

Methods for control and adjustment.

N / A


The individual collective wage developments are combined and weighted by using the wage sums.
Workers with part-time jobs and workers not covered by a collective agreement are also included in this procedure. In 2010, five out of ten workers had a full-time job and about eight of the ten employees were within the scope of a collective agreement.

What is the quality of the results.


When an index is published, the figures of all known collective agreements are incorporated. Collective agreements whose term has expired, and for which no new collective agreement has been agreed upon, are not included in the month from which the new collective agreement should have started. Also preliminary labour agreements are not included. The percentage of concluded collective agreements shows what percentage of collective agreements the outcome is based on. The agreements mentioned above concerns relative weights of the collective agreements. This weight is set by the sum of all wages that is covered by the collective agreements.

Collective agreements can also be retroactively concluded. So each subsequent month the indices are re-compiled and published.

Sequential comparability

Results of the series 2010 = 100 form a comparable sequential series. Due to a revised method this series differs from the previous one (2000 = 100).

Description quality strategy

There is a monthly verification of the availability of new information on collective wage or contractual labour costs.

Once every ten years, the basic data for the series of collective labour agreements are re-based. In December 2014 the first results on collective wage, contractual labour costs and contractual working hours are published for the series 2010 = 100.