Statistical processing
Contact info
Short Term Statistics, Business StatisticsHeidi Sørensen
+45 24 79 86 81
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Data for the statistics are collected through an electronic questionnaire. The statistics cover all ferry lines and passenger ships with goods or passenger traffic in route to or from Denmark.
The response rate is 100 percent.
Data are checked both automatically and manually at the time of data collection and in case of large deviations or missing reports the reporting company is contacted again. For a few operators the total freight weight is imputed based on the number of freight vehicles reported. The validated micro-data is aggregated and then checked for major fluctuations.
Source data
Data are reported monthly by shipping lines covering transferred vehicles, passengers and goods.
The majority of passenger- and ferry routes in Denmark are covered by the statistics as on routes with less than 100.000 pkm and 10.000 vkm are excluded. There is less than 10 of these and their traffic are estimated to be less than 0.25 percent of the total traffic.
Frequency of data collection
Data are collected monthly and published quarterly together with Maritime transport on major ports.
Data collection
Data are collected through a web questionnaire through the reporting web portal, Virk Indberet, which is the Danish digital access point to the government.
Data validation
Data are compared with previous reported data on both micro and macro level, On micro level each respondents information is compared to previous reported months and large deviations (individual assessment) will result in a new contact to the respondent to determine the reason for the development. A similar analysis is made at macro level to explain larger fluctuations.
Typical errors consist of mistyping and changes in the data sources or methodology used by the respondent. In the latter cases, the new data is assessed together with the respondent and if the new data is considered better and if so, comparable data are sought for as long a period back as possible.
The most frequent explanations are however natural fluctuations in traffic that does not result in changed reports.
Data compilation
The primary data compilation is the validation.
In certain cases where information on the amount of goods is not collected by ferry lines, imputation of total amount of goods in tonnes is done based on the number of road goods vehicles transferred.
There is no missing data since there is 100 percent response rate. No correction is made for missing data. The smallest ferry lines are not part of the statistics. Their share of total transport of passengers and goods are estimated to be less than 0.25 percent of total. There is no correction for these in the final statistics.
Adjustment
Not relevant for these statistics.