|Unit||Index 2013=100, NSA|
|Adjustments||Not Seasonally Adjusted|
For Sri Lanka, the monthly National Consumer Price Index (NCPI) measures the changes in prices paid by consumers for goods and services. Produced by the Department of Census and Statistics, the NCPI is a key indicator of inflation and is used for socio-economic analysis and policy purposes.
The NCPI is collected, processed and disseminated by the Prices and Wages division. The index is calculated using price data from all of the nine provinces in Sri Lanka.
Prior to the NCPI, price data was calculated only for specific areas within the country. From 1953 to April 2008 the DCS has compiled and disseminated a CPI for the Colombo metropolitan area only. Since May 2008 to DCS has been compiling and disseminating a CPI covering the urban areas of Colombo district.
NCPI uses data from the Household Income and Expenditure Survey conducted in 2012/13. The survey included all types of household consumption expenditures and was a good representation of all households in the country.
NCPI uses 105 sub classes of goods and services further categorized in to 12 groups. It also includes alcoholic beverages, tobacco and narcotics as an expenditure item complying with
international best practices. Conversely the CCPI (Colombo CPI) did not cover alcoholic beverages, tobacco and narcotics and had fewer sub classes and groups of goods and services.
NCPI is calculated using a two-stage Laspeyres formula. The price collected in the current period is divided by its previous period price. This short-term ratio is multiplied by the item’s estimated cost of base period spending in the previous month to obtain the current period estimate of the cost of base period spending assigned to the item. As before, the CPI is the sum of the current period estimated cost of base period spending divided by the spending in the fixed base period.
We back-extend the NSA NCPI by 60 years using three predecessors of the Colombo CPI. From it, we construct a seasonally adjusted (SA) counterpart.