Consumer price index Bonaire, St Eustatius and Saba
What does the survey comprise?
Purpose
Quarterly publication of developments in prices of goods and services purchased by consumers on the islands Bonaire, St Eustatius and Saba. Together these three islands constitute the Dutch Caribbean. The price development is presented by means of a consumer price index (CPI). Inflation is calculated as the annual rate of change of the CPI. The annual rate of change is calculated as the percentage change of the consumer price index (CPI) in a particular quarter compared to the same quarter in the previous year.
Target population
Consumer goods and services purchased by households on Bonaire, St Eustatius and Saba.
Statistical unit
Consumer goods and services.
Year survey started
2010
Frequency
Quarterly
Publication strategy
The figures for the most recent quarter are provisional. They become definite as soon as figures for the new quarter are published.
How is the survey conducted?
Survey type
The survey is based on monthly price observations at companies and institutions which supply goods and services to consumers. The monthly observations are used to calculate average prices per quarter. Price indices of product groups are calculated based on the quarterly average prices. The price indices of product groups are aggregated to calculate the CPI.
Survey method
Statistics Netherlands collects prices by visiting shops on the islands, but also by means of written surveys, internet surveys and external registrations.
Respondents
Companies, institutions, associations and government.
Sample size
On Bonaire prices are collected for about 600 different goods and services at around 125 respondents. On both Saba and St Eustatius prices are collected for about 350 different goods and services at around 70 respondents for each island.
Checking and correction methods
Statistics Netherlands checks the completeness and plausibility of the collected data. In the case of incorrect or missing data, price collectors or respondents are contacted to clarify any issues. In the case of non-response, missing data are imputed on the basis of collected data. If a product undergoes changes, , a price adjustment can be applied to account for any differences in quality between the old and the new version of the product.
Weighting
Developments in prices are calculated on the basis of a package of goods and services. Each item in this package is assigned a weight that reflects how important it is in the consumption pattern of the residents on Bonaire, St Eustatius and Saba. The weights of the various items in the CPI were initially determined on the basis of the Budget survey of the Netherlands Antilles held in 2004/2005. Since 2014 the weighting factors are based on the Budget survey held on Bonaire, St Eustatius and Saba in 2013. In 2018 the weights of the product groups have been adjusted for the new index series 2017=100. This was done by recalculating the average consumption expenditure by households in 2013 according to price levels of 2017. The weights differ between the islands.
Quality of the results?
Accuracy
The accuracy and representativity of the CPI are guaranteed by the large and varied number of products surveyed monthly through different sales channels on all three islands. The degree of accuracy cannot be calculated, however. The accuracy of price developments in each product group is generally lower than that of the total consumption package. Survey response is higher than 90 percent.
Inaccuracies can arise in various stages of the production process:
- sampling the respondents;
- selecting the representative items and estimating quality differences;
- errors during price observation;
- determining weighting factors;
- as a result of non-response.
Sequential comparability
Where possible, price developments are measured on the basis of prices observed at the same respondent in two successive quarters.
Quality strategy
The data are checked for internal consistency and completeness. If needed action is taken to verify the data. Once the data has been approved, price indices are calculated and the results are checked and validated. A second person checks the validated results.