Statistical processing

Source data

The statistic is bases on a questionnaire among construction companies. The sample is approximately 1.500 professional units. The professional units are chosen with the aid of registry information. In the sample all professional units with at least 39 registry employees have been chosen. The rest of the sample is based on random stratified sampling. There are 4 size groups, defined by the intervals 5-9 employees, 10-19 employees, 20-39 employees and at least 39 employees. The limit of 5 employees, under which no professional units are selected, has been set to reduce the burden placed on small companies.

Frequency of data collection

Data is collected each quarter.

Data collection

The figures for turnover are gathered by online reporting from the professional units in the sample. The survey is mandatory.

Data validation

The reported numbers are controlled for errors. they are compared to reported numbers from earlier periods. If the reported turnover 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 connected to wrong reports. However, the magnitude of this problem is believed to be small.

Data compilation

The reported data is scaled to the total population of professional units with main activity in construction. The population, to which we scale, include professional units with less than 5 employees, even 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 from the preceding 4 quarters.

Adjustment

No adjustments are made beyond what has been described under data validation and data compilation.