Accuracy and reliability

Overall accuracy

Environmental protection: The environmental protection table uses estimates of the environmental share of various accounting items to a greater extent than the other tables. In addition, this table contains administrative costs and revenues, the environmental share of which can be difficult to determine precisely. It is therefore estimated that environmental protection is the least accurate of the three main areas of the statistics. The table is, however, still considered to be a fair representation of its population.

Green taxes: The green taxes must be considered as the most accurate of the three main areas of statistics. This is because there is no need for estimate of the environmental share of certain taxes, and there are quite clear definitions as to whether a tax can be considered green or not.

Environmental subsidies: The environmental subsidies are closely related to environmental protection (a large part of the subsidies constitutes a subset of environmental protection) and the uncertainties that apply to environmental protection will therefore also apply to environmental subsidies. However, there is a significant difference in the sense that the many administrative items estimated in environmental protection are not subsidies. This means that the statistics for environmental subsidies contain fewer estimates, and, hence, must be considered more accurate than the environmental protection statistics.

This statistics highlight public spending and revenue related to environmental protection and resource management (including energy efficiency and renewable energy as well as green taxes). The tables of this statistics provide merely an estimate of the extent of this target. This is due to the fact that it is difficult to clearly define this broad field. Often it is not a clear-cut matter to determine whether this or the other entry in the public accounts aught to be included in the statistics or not. In some cases, it has been necessary to estimate an 'environmental share' of a given accounting item so that the item does not amount to its entire value, but only by a percentage (corresponding to the environmental share of the total item). In such cases, the estimates will typically be relatively rough. Basically, it is not possible to capture all environmentally related transactions for the sole reason that the public accounts are not detailed enough. Often, the environment is such an integral part of complex functions that it is not possible to specify it in accounting items or account shares. When trying to estimate the environmental share in a given accounts item, there will sometimes be a tendency to make this estimate larger than the target, to be sure of full inclusion. On the other hand, it is also largely unavoidable that certain items are not included. Therefore, it is not easy to determine, whether the statistics overestimate or underestimate the size of the target. The development trend, on the other hand, is expected to be reasonably reliable in the sense that once the established estimate is accepted as a functional starting point, the statistics will accurately reflect developments in the accounts over time.

When it comes to the issue of precision, it is relevant to touch the question of boundary - where are the boundaries of the population of the statistics? In most cases, it will be relatively easy to determine whether an account item should be included or not. But in some cases, an account entry can be so complicated to assess that it is not meaningful to decide whether it should be included or not. In such cases, Eurostat's environmental recommendation to omit the item is followed.

Sampling error

Since the present statistics are register-based, the sample uncertainty is not relevant in this case.

Non-sampling error

Other sources of uncertainty in the current statistics can often be attributed to different errors of measurement. In this context, the following errors deserve to be highlighted: misplacements of expenditure and revenue within the public accounts, misclassification within the two international classification systems CEPA and CReMA, as well as incorrectly included or omitted accounting items. Misplacements within the public accounts occur outside of Statistics Denmark and are therefore difficult to get the full overview of. However, the close cooperation between Statistics Denmark and accounting officers within the public sector contributes to the ongoing correction of such errors. Misclassifications, incorrect inclusions or omissions often depend on misinterpretations of the international classifications, as well as the risk of ignoring environmentally relevant account entries. Such errors are impossible to avoid completely. Efforts to reduce such errors, however, are ongoing.

Quality management

Statistics Denmark follows the recommendations on organisation and management of quality given in the Code of Practice for European Statistics (CoP) and the implementation guidelines given in the Quality Assurance Framework of the European Statistical System (QAF). A Working Group on Quality and a central quality assurance function have been established to continuously carry through control of products and processes.

Quality assurance

Statistics Denmark follows the principles in the Code of Practice for European Statistics (CoP) and uses the Quality Assurance Framework of the European Statistical System (QAF) for the implementation of the principles. This involves continuous decentralized and central control of products and processes based on documentation following international standards. The central quality assurance function reports to the Working Group on Quality. Reports include suggestions for improvement that are assessed, decided and subsequently implemented.

Quality assessment

The statistics cover the total accounts for all municipalities and regions, all ministries in the state, and all public corporations. The final accounting figures are not revised. The central government, the municipal and regional accounts and public companies are considered to be final when published. Corrections may occur later if errors in the data or in the data processing is discovered. The individual statistics have a scale and level of detail which is in line with other countries such as Sweden, Norway and the Netherlands. The accounts are established in accordance with international guidelines from Eurostat and the United Nations.

Data revision - policy

Statistics Denmark revises published figures in accordance with the Revision Policy for Statistics Denmark. The common procedures and principles of the Revision Policy are for some statistics supplemented by a specific revision practice.

Data revision practice

The differences between provisional and final years are typically small. National accounting revisions may bring data changes as long back in timelines as 3 years. This will however only seldom if ever affect the data on environmental expenditure and revenue.

In 2018, the methodological basis for the present statistics has been scrutinized. This applies in particular to the table Mreg22, which has been the subject of comparative investigations with the purpose of increasing the quality of the table (see section on the transition table in "Groupings and Classifications"). These investigations are intended to result in more fundamental revisions of the statistics over time.