Statistical processing

Source data

The statistic is bases on a questionnaire among construction companies. The sample is approximately 275 companies. The companies are chosen with the aid of registry information. In the sample all companies with at least 80 registry employees have been chosen. The rest of the sample is based on random stratified sampling. There are 3 size groups, defined by the intervals 20-49 employees, 50-79 employees and more than 79 employees. The limit of 20 employees, under which no companies are selected, has been set to reduce the burden placed on small companies.

Frequency of data collection

Yearly.

Data collection

The numbers are gathered by online reporting from the companies in the sample. The survey is mandatory.

Data validation

The reported numbers are controlled for errors. The reported numbers are compared earlier periods and total purchase from register data. If the reported numbers are substantially different from what is expected, the company is contacted to confirm the numbers. It is likely that not all errors are discovered. Therefore the statistic has some uncertainty due to erroneous reporting.

Data compilation

The reported data is scaled to the total population of companies with main activity in construction. The population, to which we scale, include companies with less than 20 employees, event though these are not in the sample. For scaling a method called ratio estimation is used. The method uses turnover information from the Danish Business Register. No numbers are imputed.

Adjustment

The statistic is yearly, so there is no seasonal adjustment.