Slovenia
Official title
Indeks cen zivljenskih potrebscin (Consumer Price Index).
Scope
The index is computed and published monthly. The index covers
the whole country and all private residential households without
any reference to the number of household members or income
limits.
Official base
December, previous year = 100. The index base is changed each
calendar year.
Sources of weights
The data source for weights is the family expenditure survey. As
the previous year is the base year for calculation of the index,
and whereas weights are revised every 4 to 5 years, at the
beginning of each year they are corrected by the price changes
between the reference period of the weights (1993) and the base
period of the index.
The latest weights of the index were derived from the Household
Consumption Survey conducted in Slovenia in 1993, covering 3,270
households. On the basis of the population census (1991)
enumeration areas were stratified in five population groups
according to the region (Ljubljana, Rest of Slovenia), to the
urban and rural area and to the agricultural area.
Then with
probability proportional to their size 654 enumeration areas were
sampled and in each of them five households were randomly
selected. The sample covered 0.5% of the Slovenian population
and is representative for the country as a whole. The survey was
conducted with a five-year frequency with a reference period of
one year. Since 1994 the survey is carried out every year.
Weights and composition
| Major groups | Number of items | Weights | Approx. No. of price
quotation
|
| Food and non-alcoholic beverages | 133 | 27.4 | ...
|
| Alcoholic beverages and tobacco | 14 | 3.2 | ...
|
| Clothing and footwear | 85 | 9.1 | ...
|
| Housing, water, electricity, gas and other | 27 | 12.6 | ...
|
| Furnishing, household equipment and maintenance | 70 | 7.5 | ...
|
| Medical and pharmaceutical products | 10 | 0.6 | ...
|
| Transport | 32 | 15.7 | ...
|
| Communications | 11 | 1.4 | ...
|
| Recreation and culture | 53 | 6.8 | ...
|
| Education | 2 | 1.0 | ...
|
| Catering services | 13 | 7.1 | ...
|
| Miscellaneous goods and services | 29 | 7.6 | ...
|
| TOTAL | 479 | 100.0 | 11,000
|
The classification is adapted, with the exception of travel
arrangements, to the COICOP/HICP classification. Some groups are
not covered yet (e.g. travel arrangements) and the coverage of
some groups (e.g. accommodation, rents, computers) is still
incomplete.
Household consumption expenditure
Household consumption expenditure refers to all financial
spending for the purchase of consumption goods and services in a
given year. Acquisition approach is used. Goods acquired on
credit terms are valued at cash purchase price. Second hand
purchases are included, but income in kind is not included.
Insurance payment for vehicles and other private insurance
(insurance connected with dwelling) are included but life
insurance payment is excluded. Contribution to health insurance
and pension funds, income and other direct taxes are not
included.
Sample selection
Current sample of items consists of 500 representative items.
Prices are observed in approximately 500 outlets in 4 urban
settlements selected in the past according to their geographical
position and number of inhabitants. The outlets in each location
are selected on the basis of the turnover data (total and by
products) from the retail trade statistics supplemented with the
price collectors' information and proposals. Two criterions are
used in selection: the coverage of the whole city area and the
representation of all types of outlets. The number of outlets by
locality and by item differs. It depends on the number of
inhabitants, turnover and number of outlets.
The representative items are selected judgementally by the price
statistics staff. Items are selected on the basis of HBS, retail
trade statistics, producers' and wholesaler' information, etc.
The varieties are selected by price collectors within the
limitation of the items' specifications. The weights of goods
and services which are not priced are added to the weights of
selected goods and services of the corresponding group.
Method of data collection
Prices are collected monthly, form the 1st to 25th day of the
month by regularly employed price collectors from different types
of outlets like supermarkets, department stores, market places,
etc. In case of such items like rail fares, electricity, water
supply, etc. prices are obtained from authorities concerned.
Prices of agricultural products are observed twice a month in up
to 5 outlets and in the open markets. Prices of manufactured
products are observed once a month in 3 to 8 outlets. Prices of
services are also observed once a month. Discounts, sale prices
and second-hand prices are not taken into account.
Housing
Rent quotations are obtained from nine standard categories of
dwellings in each of the four surveyed towns. The dwellings are
portioned by age regardless of the level of comfort. The data are
collected monthly. So as to facilitate housing cost comparison,
calculations are based on one square metre. Owner-occupied
dwellings are excluded from the index, but the weight for the
rent partly includes it.
Specification of varieties
The specifications for durable goods (cars, electronic equipment,
and household electrical appliances) are tight while the
specifications for other goods are looser.
Substitution, quality changes
Annual updating of the list of goods and services and their
specifications is the basic method for treating the changes in
the quality of goods and services. In December each year the
goods and services which are no longer representative are
replaced with those which are gaining importance. Each December,
there is a double price collection.
Price corrections due to
quality changes are seldom done during the year. In most cases
prices of the new product are directly compared with the old one.
The decision for direct comparison of prices is based on the
estimation that there are no (important) quality differences
between the two products. For non-seasonal items, which are
temporarily out of sale, as a rule, previous month price is
carried forward for a month, e xceptionally even more. In the
case of constant absence of certain non-seasonal item, it is
replaced by a new one of equivalent quality, or its price (index)
is imputed by taking into consideration prices of the same or
similar products in another outlet. Prices are adjusted on the
basis of changes of physical characteristics (weight, size).
Seasonal items
Fresh fruit and vegetable seasonal fluctuation are accounted for
by taking into consideration the weighted arithmetic average of
changes in prices of available fruit and vegetable. The weights
do not change; they are constant during the year. In case of
seasonal clothing, the last recorded price is carried forward
until new collection is on sale.
Computation
The index is computed according to the modified Laspeyres
formula. Weights from the reference weighting period are
annually harmonised with prices of December of each year and
normalised to 10,000. December of each year is thus the price
reference period, one of the index reference periods and the
linking month for the calculation of other derived indices
(current month over previous month, same month of the previous
year, average of the previous year, etc.). The present CPI
series is linked through December of each year with the old
series which was based on the basket from 1990, and transferred
to the index base 1992=100. Indices based on 1992=100 are chain
indices.
Elementary aggregate indices are calculated as the ratio between
the current and base period average prices. Average prices of
individual items are calculated as weighted arithmetic mean of
average prices in four towns. Average prices for towns are
calculated as simple arithmetic mean. Individual item indexes
are calculated by dividing the average prices in current period
with the average prices in the base period. The general index is
weighted average of individual indexes. The general annual index
and individual annual indexes are calculated as arithmetical
average of 12 monthly indexes.
Other information
None.
Organisation and publication
Price Department of Statistical Office of the Republic of
Slovenia Statisticne informacije
(Statistical Information)
On Internet web site: http://www.sigov.si/zrs