Transport and storage, price indices

Price refers to te observed prices producers get as a remuneration for their effort in the production process. Prices are exclusiv VAT and other taxes but include subsidies and discounts.

Base price refers to a price in previouse period (price reference period) against which prices in the current period are compared to.

Base year which is also known as Index reference period, is the period for which the value of the index is set at 100.

Laspeyres price index is a price index defined as a fixed weight index, and uses base period weights constant. The base period serves as both the weight reference period and the price reference period.

Elementary group refers to the lowest grouping or aggregate in an index estimation hierrchy. An elementary index is a relative price change between current peiode and the price reference period.

Jevons index is an elementary index defined as the unweighted geometric average of the current to base period price relatives.

Weight shows to the value share og a group of products or services that constitute an index component. A weight share of an index component defines how important that component is in a given index.

Business to Business (B2B), Business to Consumers (B2C) og Business to All (B2All) refers to whom the services are delivered to. For Passenger air transport, the distinction between B2B and B2C is made depending on whether a ticket is flexible or not.

The applicable standard industrial classification is Statistics Norway's standard industrial classification, SIC 2007. SIC 2007 is developed based on EU's standard NACE Rev. 2.

Name: Transport and storage, price indices
Topic: Prices and price indices

Transport, Tourism and ICT Statistics

Only at national Level.

Frequency: Quarterly.

Timeliness: The reference period is one quarter (i.e., 3 months). The index is published within 60 days after the end of the reference period.

The indices are reported to Eurostat quartely.

Data are stored as text files on UNIX.

The purpose of the statistics is to measure the price development for Transport and storage services in SN 2007, the Norwegian equivalent of the EU Standard Industrial Classification.

Industries that are covered with price indices within transport and storage are freight transport by road, sea transport, passenger air transport, storage and warehousing, cargo handling services, and postal and courier services. The indices go back to first quarter of 2006 with the exception of freight transport by road that starts from the fourth quarter of 2004.

The indices' base year (reference year) was originally set to 2006 (i.e. 2006=100) but was changed to 2010=100 in 2013.

Research institutions, industry organisations, public authorities and the media. The indices are also used to deflate the National Accounts.

No external users have access to the statistics and analyses before they are published and accessible simultaneously for all users on ssb.no at 08 am. Prior to this, a minimum of three months' advance notice is given inthe Statistics Release Calendar.

Statistics Norway produces Turnover index and Structural business statistics for all industries within transportation and storage services.

Sea transport : The index is used in National Accounts. The Consumer Price Index has an index on passenger transport by sea.

Passenger air transport : Statistics Norway produce Structural business statistics for the industry. Tickets for leisure travevls are also presented as a sub-index in The Consumer Price Index . When comparing the Consumer price index (CPI) and the Service producer price index (SPPI) it is important to keep the following considerations in mind:

• Objective - While the CPI measures the price development for households, the service producer price index measures the price development for the producer that together with volume gives the producers' turnover. These two prices may differ due to fees and taxes that are collected on behalf of a third party (i.e.: VAT to the tax authorities or security charges to the airports)
• The differences in method of data collection reflects the differences in the objective. While the dataset for the SPPI consist of list prices (per 15. every month) and actual volume, the data for the CPI is compiled by mimicking the actual consumer behaviour - i.e.: Orders are simulated on the internet and are held constant between periods.

Freight transport by road : The index may be used in the National Accounts. Cost index for road goods transport is also published for the industry.

The Statistics Act, Sections 2-1, 2-2 and 2-3.

Regulation (EC) No 1158/2005 of the European Parliament and amending Council Regulation (EC) No 1165/98 concerning short-term statistics.

The industries are classified according to the Norwegian standard industrial classification, SN 2007. The statistical unit is the enterprise in all but freight transport by road and cargo handling services where the statistical unit is local kind-of-activity units (local KAUs).

The indices fall under section H - transport and storage in SN 2007. The population coverage is detailed below:

Index for freight transport by road: The population embraces all local kind-of-activity units with in class 49.41

Sea transport : The population comprise all active enterprises within division 50.

Passenger air transport index : The population encompasses all Norwegian enterprises within group 51.1.

Storage and warehousing index : The population is defined as all enterprises with in group 52.1.

Cargo handling : The population is defined as local kind-of-activity units belonging to 52.24, operating in harbours and running stevedoring facility.

Postal and courier services : All enterprises within division 53.

Quarterly survey data, register data, and turnover data from the structural business statistics constitute the data source.

Statistics Norways business register (VOF) is the main source in identifying the population frame, and drawing samples. In the case of class 49.41 (SN 2007), VOF is suplemented by a vehicle register from the Norwegian road transport authority (Statens vegvesen).

The samples are drawn predominantly using random sampling techniques. A combination of random and non random sampling such as Purposive samples is employed to augment the representativeness of the sample where the largest sample unites are selected with certainty while the rest are drawn on brobablistic basis.

A cut off threshold is also applied in some cases to limit the population where the industry is more of a homogenious nature or where units falling below the cut off limit constitue a negligible market share. Turnover size or number of employees is used as cut off criteria. Sample units in industries with large populations size are rotated to reduce respondent burden.

Data is collected electronically using a web questionnaire with the exception of the industry Passenger air transport. The enterprises in this industry provide their price categories and the number of sold tickets within each price category. The questionnaires are made available on Statistics Norway's website and the respondents are notified by mail.

The questionnaire is controlled and revised both automatically and manually. The price data goes through several statistical editing to identify the most critical and unusual observations. If price changes seem unlikely large the respondents are contacted.

At the bottom of the aggregation process, an elementary index is estimated as a geometric average of price relatives between the base period and the current period. The elementary indices are then weighted togather following a criteria defined for a given indeks. The process of agregation repeats itself to the highest agregation level to finally yield a total indeks as a weighted average of price relatives of all activities in the industry.

The index is agregated using a Laspeyre index methode. Weights are fixed for one whole year with the exception of the price index for air transport that adjusts its weights every month. The weights are based on turnover which is obtained either directley through the survey or from structural business statistics.

Eurostat requires indices' reference year to be set to 2006=100. For the indices that were developed post 2006 and survey data was lacking, an industry's indeks values are estimated earnings indeks that is closely correlated to the service price index.

Not relevant

The use of collected data is in accordance with Statistics Norways Statistical Act.

Norway Post has allowed Statistics Norway to publish the index about postal activities under universal obligation.

The calculation method has remained unchanged thoughout the period.

First quarter of 2015 the indices associated with industry group Passenger air transport were revised going back to first quarter of 2006. The new figures were calculated using weights that more accurately reflect the distribution of turnover among enterprises in the industry.

Measurement error might generally arrise due to:

1) The respondent might report the same price even though price has actually changed.

2) The respondent report prices on different services than the ones covered by the questionnaire.

Data editing routines at micro and macro level controll for measurment error. If measurement error is suspected, the respondent is contacted to get the right price.

Non-responses exists either when respondents do not return the questionnaire or when the questionnaire is only partially completed. About 98 per cent of the sample returns the questionnaire.

A sample can be skewed if som services or enterprises are less represented than the realities in the market. Such skewness could then result in biases and unstable fluctuations in the index estimates.

To reduce sampling error and hence skewness, samples are designed to include major market agents. In addition, the sample is stratified to enhance inclusiveness. Sample rotation is another technique Statistics Norway employs to reduce skewness in cases were the population size is big enough.

Standard deviation is calculated for all index estimats. Indices with few observations tend to be less significant.

Other sources of error may include quality change in the service provided. In the long run the service's product characteristics may gradually change. Quality change my also arise as a result of enhancement in productivity.

Not relevant