Trinidad and Tobago
Official title
Index of Retail Prices.
Scope
The index is compiled monthly and covers households, with monthly
income between 400 and 4600 dollars in 1988.
Official base
September 1993 = 100.
Source of weights
The weights were obtained from the Household Budget Survey
carried out in 1988 and covering a sample of 2,4393 households,
including 1,369 households with a monthly income of between 400 and 4600
dollars in 1988. The weights were not adjusted to take
into account price changes between the survey period and the base
period. Items with weights equal to or greater than 1 per 1000 were
selected for inclusion in the index.
Weights and composition
| Major groups
| Number of items
| Weights
| Approximate number of price quotations
|
| Food
| 94 | 351 | ...
|
| Meals taken outside home
| 4 | 15 | ...
|
| Alcoholic drinks and tobacco
| 6 | 47 | ...
|
| Clothing and Footwear
| 5 | 26 | ...
|
| Housing
| 5 | 126 | ...
|
| Household operations
| 11 | 12 | ...
|
| Household Supplies and Services
| 44 | 84 | ...
|
| Healts and Personal Care
| 5 | 14 | ...
|
| Transportation
| 45 | 189 | ...
|
| Recreation, reading and Education
| 13 | 86 | ...
|
| Total
| 6 | 25 | ...
|
| Major groups
| 8 | 25 | ...
|
| Major groups
| 246 | 1000 | (a) ...
|
Note: (a) Genaraly, three price quotations are collected for each item.
Household consumption expenditure
Consumption expenditure for the purpose of the index comprises
all expenditure on goods and services for consumption, including
insurance and mortgage interest rates relating to housing.
Income in kind is included as income if received on a regular
basis. Gifts and licence fees are also included. Excluded from
the index are income taxes and other direct taxes, contributions to
social insurance and pension funds, insurance associated with
specific consumer goods, health care and life insurance payments.
Method of data collection
Prices of commodities and services are obtained from 429
selected outlets. Localities were selected on the basis of
information provided by the households included in the HBS and
field staff's knowledge. Collection of price data is the
responsibility of the Chief, Census and Surveys Officer who has
ten field officers visiting selected outlets periodically and
collecting the required data. Prices of vegetables, fruit and meat are
collected twice a month. Prices are collected each month for other
food, drink and tobacco, clothing, health and pertsonal care and each
quarter for house repairs and maintenance, meals out, rent, household
supplies and services transportation. Prices for fuel and light, now
renamed Household Operation, are collected quarterly.
Price data on education are collected twice a year.
Price collection starts on
the second Wednesday of the month and continues for one week.
The prices used in the index are those that any member of the
public would have to pay on the pricing day to purchase the
specified good or service.
Sale prices are excluded unless they account for a large
proportion of sales during the reference period. Black-market
prices are taken into account if quoted by the retailer.
Discount, hire-purchase or credit terms, and second-hand
purchases are not included.
Housing
Rent data are collected each quarter from selected dwellings varying
from one to three bedrooms. The total current rent data for a
particular pricing area is expressed as a relative of the total
base rent data of the respective area. The area relatives are
combined into a final relative using the area weights. An
imputed net rent for owner-occupied housing was obtained from the HBS.
Owner-occupied housing cost inclides mortgage interest payments,
insurance, water and sewage rates, taxes, repairs and maintenance.
These expenses were treated as indicators items for monitoring
movements in imputed rents of owner-occupiers.
Specification of varieties
There are detailed specifications of the brand, quality, unit
etc., for the varieties selected for pricing.
Substitution, quality change, etc.
Whenever the characteristics of the products are altered,
adjustments are made on base year prices. Obsolete items and
items disappearing from the market are replaced by suitable new
substitutes.
Seasonal items
Seasonal fresh food items are omitted from the index during their
off-season and their weights are distributed among the remaining
items in the same group.
Computation
The index is computed according to the Laspeyres formula as a
weighted arithmetic average with fixed base, using weights
corresponding to the base period.
Average prices of items for each area are first calculated as
simple arithmetic averages of the price quotations.
Separate price relatives of items for each area are then
calculated by dividing the average price of the current period by
the average price of the previous period. These price relatives
are weighted together to arrive at national price relatives using
area weights that are based on the population and retail sales
data of the areas concerned.
The method of linking is the simple aritmetical method.
Organisation and publication
Central Statistical Office: The Index of Retail Prices 1993 -
Statistical Studies and Papers
, No.II.
Government Printing: Gazette of Trinidad and Tobago
(Port of Spain), Economic Indicators Report, Statistical Digest of the
Central Statistical Office.