Mexico
Official title
Indice nacional de precios al consumidor (National Consumer Price
Index).
Scope
The index is computed monthly and covers all urban consumers of
the country.
Official base
1978 = 100.
Source of weights
The weights and selected items were mainly derived from a national
income and expenditure survey conducted in 1977.
Weights and composition
| Major groups
| Number of items
| Weights
| Approximate number of price quotations
|
| Food and tobacco
| 141 | 37.39 | 60000
|
| Clothing and footwear
| 45 | 9.88 | 40000
|
| Housing
| 6 | 17.77 | 20000
|
| Furniture, furnishings and household equipment
| 34 | 6.21 | 5000
|
| Personal and medical care
| 28 | 5.81 | 4000
|
| Transport
| 17 | 11.25 | 4000
|
| Education and recreation
| 23 | 5.75 | 5000
|
| Other services
| 8 | 5.94 | 2000
|
| Total
| 302 | 100.00 | 140000
|
Household consumption expenditure
Not available.
Method of data collection
Prices for food items and tobacco are collected each week. Prices for
the other items are ascertained every two weeks. The prices used to
compute the index refer to those actually paid by consumers: net and
cash prices (including taxes, rates and discounts if the latter was in
force at least more than half of the days included in the price
collection period).
Housing
Rent quotations for the 35 towns included in the index
are obtained from approximately 10,000 dwellings visited
directly by agents.
Specification of varieties
Not available.
Substitution, quality change, etc.
If the specification of a product changes, the linking method is
adopted. If an item disappears from the market, it is replaced
by a similar item using the linking method and, if necessary, a
quality adjustment is made so as to ensure the principle of
constant quality.
Seasonal items
Seasonal fluctuations in the prices of certain items are taken into
account by maintaining the closing price of the previous season during
the off season.
Computation
The index is computed according to the Laspeyres formula as a
weighted arithmetic average with fixed base, using weights
corresponding to 1977.
Price relatives for each variety in each outlet are
first calculated by dividing the average price for the current
period by the average price for the base period. A simple
arithmetic average of price relatives of varieties representing
an item is then computed to arrive at an item index. Separate
indices are calculated for the 35 towns. The national index is a
weighted average of the indices for the 35 towns, the weights being
proportional to the consumption expenditure of each town.
Organisation and publication
Banco de México, Subdirección de Investigación Económica:
Indicadores Económicos
(Mexico).