About the statistics

1. Administrative information

1.1. Name

Index of retail sales

1.2. Subject group

08.03.20 - Turnover

1.3. Frequency and timeliness

Monthly. The statistics are normally published on the 28th or 29th day of the following month.

1.4. Regional level

No geographical breakdown available. National level only.

1.5. Responsible division

460 - Division for Construction and Service Statistics

1.6. Legal authority

The Statistics Act, § 2-1, 2-2 and 2-3

1.7. Legal document(EU)

EU Council Regulation No 1165/98. Commission Regulation 586/2001.

1.8. International reporting

The statistics are reported to Eurostat at the time of publication in Norway.

2. Background and purpose

2.1. Purpose and history

The index covers total retail sales of all goods excluding motorised vehicles. It is regarded as an important short-term indicator of consumer demand and has been published since 1936.

From November 1999, the sample of retail stores has been supplemented gradually with turnover figures for chain stores reported directly by head office. As a consequence, figures for newly established and closed down units for the above-mentioned stores are also more up to date.

2.2. Users and applications

Users include public and private sector agencies and organisations. Statistics Norway's national accounts statistics rely on timely production of the retail sales index. Other users include Statistics Norway’s research department.

3. Statistics production

3.1. Population

All establishments in retail trade, except of motor vehicles and motorcycles (SN2007: 47.).

3.2. Data sources

Monthly statistical surveys (simplified questionnaire), Statistics Norway’s annual survey of retail trade establishments (detailed questionnaire), the VAT register and Statistics Norway's Register of Establishments and Enterprises.

3.3. Sampling

A sample of about 15 500 units is selected from the population of retail trade establishments in the VAT register, representing about a quarter of all units. This includes a sub-sample of 13 200 chain stores with direct reporting from head office.

Another sub-sample of 2 300 units is selected from other existing establishments, i.e. independent shops and the remaining chain stores not yet included in the sample above. This population is stratified according to size in terms of number of employees. The sample is adjusted as necessary to ensure a reasonably even geographical coverage and to incorporate available new information from the annual survey of retail trade establishments and the bimonthly updated VAT register. In the latter case, the adjustments focus on diverging trends between turnover as measured by the sample and turnover as measured by a survey of the VAT register. In 1997, the sample was adjusted to take into account the variation of strata variances. The sample is rotated annually based on the second term of the turnover statistics. Establishments are retained in the sample for a maximum of four years unless they are part of a full coverage stratum.

3.4. Collection of data

Questionnaires are submitted by mail, via the Internet or electronically. If the respondents need help in filling in the questionnaire, Statistics Norway can be contacted by telephone. The establishments normally receive the questionnaire before the expiry of the survey month. The deadline is the 12th day of the following month. Failure to respond is subject to fines.

3.5. Control and revision

Prior to the statistical compilation, arithmetic and logical checks are carried out. This procedure also includes comparing the results with other data sources, mainly the wholesale and retail trade statistics.

Results broken down by sector and stratum are compared with data for the previous period and the corresponding period in the previous year. If the discrepancy is considerable, the respondent is consulted.

3.6. Estimation

A ratio estimator is applied to each stratum to inflate sample data to population level. The ratio estimator uses turnover figures from the VAT register as auxiliary variables.

The establishments are divided into identical units and newly established units. These concepts are defined in Notater 93/17 Detaljomsetningsindeksen (in Norwegian only).

Newly established units are enterprises that have been registered in the Central Register of Establishments and Enterprises after the last rotation of the sample. The turnover of these enterprises is based on estimates as this information is not available. The estimates are based on information about newly established units in the same period in the previous year. The average turnover per establishment is calculated for newly established units in the same period in the previous year. On this basis the turnover for all recent establishments for the period in question is aggregated. The estimates for newly established units are made on stratum and NACE level.

Volume indices at NACE four-digit sector level are calculated by deflating value indices directly by means of the price index for retail sales. At NACE two and three-digit sector level the volume indices are calculated as a weighted sum of the volume indices at the NACE four-digit sector level using value shares in the reference year as weight.

The index is adjusted for seasonal variations applying the X12ARIMA method with non-fixed seasonal effects and multiplicative model. As a supplement to seasonal variations, the new model takes into account the effect of weekdays, fixed holidays as 1st and 17th May, Easter, Pentecost, Ascension Day and 1st New Year's Day. 24th to 26th of December are considered as seasonal variations with a method developed by Statistics Norway.

3.7. Confidentiality

Not relevant.

4. Concepts, variables and classifications

4.1. Definitions of the main concepts and variables

Turnover includes dutiable and duty-free sales income from goods and services as well as rents, commission fees and royalties. Financial revenues are not included.

4.2. Standard classifications

Standard Industrial Classification (SIC2007) (http://www.ssb.no/nace).

5. Sources of error and uncertainty

5.1. Measurement and processing errors

Measurement errors (the respondent supplies erroneous data) and processing errors (wrong interpretation of figures and letters during optical scanning) may occur.

Three types of errors are common:

Control routines are in place to prevent measurement and processing errors. The questionnaires are optically read or downloaded from the Internet and the data checked automatically before the questionnaires are filed. The questionnaires are stored in digital form, which facilitates manual control of submitted forms and registered data. The scope of collection and processing errors is unknown.

5.2 Non-response errors

Reminders are sent to enterprises that fail to respond in time. Failure to respond is subject to fines. Large enterprises that do not respond are reminded via telephone shortly before publication. These enterprises are treated in the same way as enterprises that are not included in the sample. This means that the change in turnover applied to these enterprises is the average percentage change that is applied to their stratum. Non-respondents normally constitute about 4 per cent of the total sample at the time of publication.

5.3. Sampling errors

The results are uncertain as they are based on information from a sample of enterprises. The sample is updated once a year. The coverage exceeds 80 per cent of the population in terms of turnover, including the sub-sample of chain stores. Sample variance accounted for by the sub-sample of other stores than chain stores is estimated to about 1 per cent. Sample errors may also occur as a result of errors in the information that the sample is stratified according to.

5.4. Other sources of error

Not relevant.

6. Comparability and coherence

6.1. Comparability over time and space

The index has been published since 1936. A new version of Norwegian industry classification (SIC2007) has been implemented from January 2009. The toal index, as well as three-digit sector levels, has been recalculated back to 2000 according to SIC2007. In January 2003, Statistics Norway altered the calculation method for the price index of retail sales. The new method is based on the price development of product groups from the consumer price index, as well as on sector-wise product allocation. The product allocation comes from a survey with that particular focus. The price index of retail sales is calculated using the same methods used to calculate the deflator of the retail sales component in the index of household consumption of goods. Volume figures have been calculated back to August 1999 using the current deflator.

The volume indices at NACE four-digit sector level are calculated by deflating value indices using the aid of the price index for retail sales. From January 2002, volume indices at NACE two and three-digit sector level are calculated as a weighted sum of the volume indices at NACE four-digit sector level with value shares in the reference year as weight. In the past, volume indices at the NACE two and three-digit sector level were calculated using immediate deflation of value indices.

6.2. Coherence with other statistics

The index of household consumption of goods is published at the same time as the index of retail sales. The former is more extensive than the latter, which can lead to different developments in the two indices. Price indices of retail sales are applied when calculating the volume indices of the retail sales index. Changes in turnover are later compared with bimonthly retail sales statistics, which are based on the VAT register.

7. Availability

7.1. Publications and other links

The retail sales index is published monthly on http://www.ssb.no/doi_en/. Main results are published in other publications, such as the Statistical Yearbook and the Economic Survey.

Documentation:

- Næs, P. og Solheim, L. (1993): Detaljomsetningsindeksen, Notater 93/17. - Solheim, L. (1989): Den månedlige detaljomsetningsindeksen, upublisert notat. - Seliussen, I. (1997): Utvalsstandardavvik i detaljomsetningsindeksen, Rapporter 97/24. - Pham, D.Q. (2007): Ny metode for norsk påskekorrigering for norske data, Notater 07/43.

7.2. Microdata

Primary data and compiled statistics are stored electronically in SAS files.


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