Nigeria 1
Official title
Urban Consumer Price Index - All Income Groups.
Scope
The index is compiled monthly and covers households of all income
groups in urban areas.
Official base
1975 = 100.
Source of weights
The weights and selected items were derived from a household expenditure
survey conducted in 1974-75 in urban areas among households of all
income groups.
Weights and composition
Not available.
Household consumption expenditure
Not available.
Method of data collection
The prices are collected by agents, from markets and local stores. The
frequency of price collection for each item depends on the variability
of its price, and ranges from daily (for food items) to monthly (for
other items).
The prices used to calculate the index are the retail prices actually
paid.
Housing
Not available.
Specification of varieties
The specifications of items to be priced are given in terms of
brand, make, quality and size.
Substitution, quality change, etc.
If an item is not available, a similar item is substituted, and a
linking method is used in the calculation. If this is not possible, the
last recorded price of the item is repeated.
Seasonal items
Seasonal items such as fresh fruit and vegetables are priced only
when they are in season.
Computation
The index is computed according to the Laspeyres formula as a
weighted arithmetic average with fixed base, using weights
corresponding to the period 1974-75.
Separate indices are first calculated for low-, middle- and
high-income groups in each centre. The price relative for each
item within each centre is computed by dividing the average price
for the current period by the average price for the base period.
Urban-centre indices are combined to obtain the index for all
income groups in urban areas.
Other information
A new series is now computed for urban areas (base September 1985 = 100)
but the relevant methodological information was not available in the ILO
at the time the present volume was published.
Organisation and publication
Federal Office of Statistics: Retail prices in selected
centres and consumer price indices
(Lagos).
Idem: Retail prices in selected centres and consumer price
indices
(March 1978).