As of January index, published 10th of February 2012, changes are made in the price index of food and non-alcoholic beverages and the price index of medical products.
In the price index of food and non-alcoholic beverages, which is entirely based on retail scanner data from the Norwegian grocery market, a method for dealing with missing values is introduced. This change is made due to indications of a downward bias partly as a result of an increased sales activity in combination with missing values. Introducing a method for dealing with missing values contributes to reduce the bias in the index. Seasonal items only available during a certain period of the year, have until now been excluded from the price index of food and non-alcoholic beverages due to lack of satisfactory treatment. From January 2012, seasonal items are included in the index as a result of the introduction of estimations for missing values.
In the price index for medical products the product range will be greatly expanded. Statistics Norway has received scanner data on medical products for several years, but has only used data for some representative items. From January 2012, the index will include almost all the products that consumers purchase. As before, the index will be calculated using an unweighted geometric average at elementary level.
In addition, smaller adjustments are made in the price index of airline fares. As of January index 2012, prices of an additional departure day are registered each month, at the same time the number of price measurements prior to the departure is reduced.
The publishing levels are not affected.