Tunisia
Official title
Indice spécifique des prix à la consommation (Specific Consumer
Price Index).
Scope
The index is computed monthly and covers urban households of
employees with an annual expenditure of between 160 and
250 dinars per person in 1980.
Official base
1983 = 100.
Source of weights
The weights and selected items were derived from a household expenditure
survey conducted in 1980. The weights were not adjusted to take account
of changes in prices between the survey period and 1983.
Weights and composition
| Major groups
| Number of items
| Weights
| Approximate number of price quotations
|
| Food
| 164 | 503 | 25000
|
| Housing:
| | |
|
| Rent and rates
| 2 | 33 | 64
|
| Fuel and light
| 16 | 62 | 512
|
| Furniture, household equipment and maintenance
| 60 | 78 | 1924
|
| Personal and medical care and cleaning materials
| 127 | 56 | 4064
|
| Transport
| 25 | 54 | 800
|
| Clothing and footwear
| 91 | 101 | 2910
|
| Education, recreation and other
| 69 | 113 | 2210
|
| Total
| 554 | 1000 | 37484
|
Household consumption expenditure
Household consumption expenditure for calculating
the index corresponds to the goods and services
usually purchased by the urban population and includes credit
purchases which are recorded in full. The following
are excluded: income in kind, goods produced by households for
their own consumption, rental value of owner-occupied housing,
down payments for the purchase of new goods, the purchase of
housing and land, national insurance and pension contributions,
life insurance premiums, the cost of trading licences, insurance
of specific consumer goods (apart from private vehicle
insurance), direct taxes, remittances of funds, donations and
similar payments.
Method of data collection
The prices are collected by agents at markets and from retail
outlets and service establishments in the 16 largest towns in the
country. The retail
outlets selected in the towns are representative of all
forms of trade in each type of quarter
(medina, modern and outlying quarters). The price quotations are
collected systematically at all supermarkets, at 55 markets, 322
groceries, 240 clothing shops and 785 service establishments.
Public rates are recorded directly at the public services
concerned. The price survey is conducted by means of direct
contacts using agents appointed on a permanent basis. In practice,
there is one agent per district, with the exception of Tunis and
Sfax where there are three and two agents respectively due to
the size of these towns. The prices for most items are collected
once a month at each retail outlet, apart from the prices of
fresh fruit, vegetables and fish which are collected every day at
the markets. This rate of collection means that two to three
prices per variety can be obtained at the end of each
month. The staggering of observations over the course of the
month depends on the planning of visits to retail outlets.
The daily average prices of fresh products are
generally the prices recorded in the morning (from 10.00 to
12.00) at the markets. Clearance sales, reductions, hire
purchase and credit purchases are not taken into account.
Housing
Rent quotations are obtained every six months from a sample of
2,000 tenants of apartments, villas and Arab houses, and
include the monthly cost of the rent and, where appropriate,
rates. The calculation of the rent index takes account of the
size of each type of dwelling.
Owner-occupied dwellings are not covered in the index.
Specification of varieties
In order to follow the progress over a period of time of the
price of the same good or service of similar quality so that any
changes in price are pure price variations, the varieties are
determined by the agents at each retail outlet and an indication
is made of the make, the volume, the weight, etc.
Substitution, quality change, etc.
Varieties that have been under observation for a
certain length of time may disappear from a certain retail outlet or
from the market. The disappearance of a
product is considered temporary until it passes the six-month
mark, after which the disappearance is considered as final and a
replacement is sought.
The substitution method differs according to the nature of
the variety. In the case of heterogeneous varieties, the agent
proceeds with the replacement in accordance with the retail
outlet and changes the base price of the article in the shop if
there is an appreciable difference in quality.
In the case of homogeneous varieties, if the replaceable
variety is comparable to the one that has disappeared (only a
different make), the agent is permitted to substitute it without
altering the base price.
Seasonal items
Fresh products such as fruit, vegetables and fish are
characterised by frequent price fluctuations, and also by
variations in the volume of production, depending on the season.
For this reason these products are not treated in the same way as
the other ordinary varieties included in the index basket.
The index for fresh products is calculated by using the
price ratios of the current month and of the same month during
the base period. These indices are then weighted and moving
averages are used in the computation of the final index.
Computation
The index is computed according to the Laspeyres formula as a
weighted arithmetic average with fixed base, using weights
corresponding to 1980.
First, simple average prices are calculated for each district in
the case of homogeneous varieties, and simple average indices are
calculated for each district in the case of heterogeneous varities.
From the district to the regional level, the urban population of each
district is used as the weight. From the regional to the national
level, the weights used are in accordance with the structure of
consumption expenditure in each region.
Other information
Detailed sub-groups are published in the Bulletin mensuel de
statistique
and also another national index: Indice général
des prix à la consommation familiale
(base 1983=100).
Organisation and publication
Institut national de la statistique: Bulletin mensuel de
statistique
(Tunis).
Idem: Annuaire statistique de la
Tunisie
.
Idem: Economie Tunisienne en chiffres
.