What does the survey comprise?
The annual publication of average prices of consumer goods and services.
Consumer goods and services purchased by Dutch households.
Consumer goods and services
Year survey started
In 2010 the publication of average prices was restarted. The table “Average prices of food since 1800" includes prices from the year 1800. The table "Average prices of consumer goods since 2000” " includes prices from the year 2000.
All figures are definite when published.
How is the survey conducted?
The study is based on monthly price observations at companies and organisations that supply goods and services to consumers.
Although many prices are observed by interviewers in retail outlets, more and more retail chains also provide price-data sets (scanner data). Statistics Netherlands also uses written and telephone surveys, internet monitoring, external registrations and brochure/catalogue information.
Companies, institutions, associations and authorities.
Products and services from over 1,800 respondents.
Checking and correction methods
Statistics Netherlands checks the completeness and plausibility of the incoming data. If the data are incomplete or implausible the respondent is asked to provide more information.
If the calculation of the average price of an item is based on more than one item and/or more than one sales channel, weights are assigned to the items and/or sales channels, based on the weights in the CPI. Where necessary, external sources are used for a more detailed weighting of sales channels. The consumption expenditure of National Accounts is used to determine the weights of the various goods and services in the CPI. In addition, budget surveys and other external sources are also used.
Quality of the results
The accuracy and representativeness of the average prices are guaranteed by measuring prices at different sales channels across the country. Each month the prices are measured at different sales channels throughout the country. By weighting the various sales channels, inaccuracies as a result of changes in the sample of respondents are minimised. Over the period of one year, some 800 prices (excluding scanner data) are used to calculate the average price for a certain item. However, it is impossible to calculate the degree of accuracy.
Inaccuracies can arise at several stages in the production process:
• sampling respondents
• measurement errors
• determination of weighting factors
The average prices are calculated for the most common item in the period concerned. As a result, prices are not always comparable over time: the annual car inspection, for example, was not comparable in 2001 and 2003, as car owners were required to replace old license plates in 2003.
The data are checked for internal consistency and completeness. When necessary, action is taken to verify the data. If the data are correct, the price indices are calculated and the results are verified and validated. Validation is done by another department.