Accuracy and reliability

Overall accuracy

Only 2,301 households out of 17,730 selected households chose to participate in the Household Budget Survey 2022. For the total consumption for the entire population, there is an uncertainty margin of +/- 1.2 per cent, so that the total consumption, which is estimated at DKK 359.661. with 95 percent certainty, it is expected to lie between DKK348,434 and DKK 370,888. For individual groupings in the population and product groups that are rarely traded, the uncertainty is greater. The consumption is thus more precisely calculated for, for example, households with higher incomes or where the main income recipient is of Danish origin, is in work, is over 60 or has education beyond primary school, as there are relatively more of these groupings who participated in the survey.

Sampling error

The total sample for the Household Budget Survey 2022 consisted of a total of 17,516 households drawn in respectively 2021 (9551) and 2022 (8.179).. In 2022, 1,123 households participated, while 1,178 households participated in 2022 a total of 2,301 for FU2022. The participation rate for the Household Budget Survey 2022 was thus 13 per cent. Sample uncertainty is calculated for the individual consumer product groups based on the households that have chosen to participate in the survey. In the Household Budget Survey 2022, the sample uncertainty is based on the responses from 2,301 participating households. The sampling uncertainty is quantified by the coefficient of variance (the relative standard error).

The coefficient of variance for the total consumption per household in the Household Budget Survey was 1.2 per cent. This means that at 95per cent the confidence interval for the total consumption per household is DKK 359.661 +/-5,728.

There is great variation in the sampling uncertainty between total consumption and specific consumptions categories. Consumables that are bought often have a lower sample uncertainty than consumables that are seldom bought.

Bread, for example, is a product group that most households often buy during the week-long accounting they have had in connection with participation in the survey. The coefficient of variance on bread for an inspection household is 2 per cent, while that for eg preserved milk is 28 percent.

Similarly, the coefficient of variance is 3,9 percent in the region of the capital, while it is 7,4 percent in the region of Zealand. Tables on https://www.dst.dk/consumption.dk shows the detailed coefficients of variation.

Non-sampling error

The sample basis for the study is inhabited private household addresses in Denmark for a given year. The pull-out frame contains not only private households, but also common households. Attempts are made to avoid this in the Household Budget Survey, by only extracting households with a maximum of 8 inhabitants. This may give rise to a bias in that we do not extract large private households (households with more than 8 people), but this problem is estimated to be minimal.

The framework population is based on two calendar year populations and must affect the target population in one given year. The target population is thus represented by a framework population from 2021 merged with one from 2022. In general, the framework population, which is based on 2021, largely covers 2022. However, some households may change character from 2021 to 2022.

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 Household Budget Survey is a sample survey, combined with a wide range of register variables. The survey is based on a simple randomly drawn sample. The survey has over a number of years been conducted by the same procedure.

The study's annual sample is not large enough to only give a reliable estimate of consumption. Therefore included sample data from the previous years also in the total charge for the year. The study has the character of a sort of "moving average".

Through several years the study has been conducted by the same procedure. This has been conducted partly to ensure a better comparison over time and partly to provide faster results and to minimise errors.

The Household Budget Survey was in the period 1994-2013 based on a three-year sample. From 2014 and onwards, the Household Budget Survey is based on a two-year sample. This is an improvement of the Household Budget Survey, since the figures brought forward by 12 months.

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

Since the publication of the Household Budget Survey 2017, there is only an annual publication, therefore no revisions will be made in the future.