Nigeria 2
Official title
Composite Consumer Price Index - Rural and Urban Areas.
Scope
The index is compiled monthly and covers households of all income
groups in both urban and rural 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 and rural 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 a centre is computed by dividing the average price for
the current period by the average price for the base period.
The national index is the weighted arithmetic average of the indices
for urban and rural areas, and for low-, middle- and high-income
group families. The weights used are proportionate to the population of
the areas concerned.
Other information
A new series is now computed for urban and rural 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).