Questionnaires are sent by post or over the Internet. Establishments normally receive the questionnaire around the 15th in
the second month of the quarter. The submission deadline is approximately two weeks later.
There are logical controls in the data entry routine, big difference in price compared to previously provided, and missing
price or percentage of groups will be checked and corrected if needed.
For each respondent the reported prices are compared with the prices reported in the previous quarter. Longer data series
for prices are also evaluated. Finally, prices of the same commodity are compared. In case of any major differences respondents
are contacted by telephone. When a price is missing, the company is contacted by telephone. If the commodity in question is
discontinued, the company is asked to report the price of the most similar commodity.
Price changes are compared with the Price index of first-hand domestic sales.
The calculation of the index use the formula of Laspeyres type. The index is calculated in 6 steps;
Step 1: For each establishment in the sample the index is computed for the representative commodities that have prices in
the base period and the calculationperiod.
Step 2: A price index is computed for each group of commodities as an unweighted average of the representative commodities
within the group of commodities.
Step 3: An index is computed for establishments as a weighted average of the index of the group of commoditites.
Step 4: A price index for each stratum within a group of industriy is computed as an unweighted average of the price indices
for the establisments within the stratum. The establishments are divided into 3 stratum based on the establishments' Revenue.
The stratums varies between different industries.
Step 5: For each group of industry a price index is computed as a weighted average of the price indices for stratums with
revenue within each stratum as weight.
Step 6: The price indices for groups of industries and main industries, in addition to whole sale trade as a whole is computed
as a weighted average following the same Method. For each level the indices are weighted as a whole together with corrosponding
ratio of Revenue and are summed.
From the establishments information about the weights for the different groups of commodities are also obtained. The revenue
for each stratum and each group of industry is obtained from the wholesale and Retail trade statistics. The Revenue from the
most recent publication of the mentioned statistics is used as weights.