Sources & Methods


The Retail Price Index (RPI) serves as an economic indicator that measures the inflation in Malta, mainly determining the monthly average change in the prices of goods and services purchased by private Maltese households.  Every month, indices for each item are calculated to derive the annual and monthly inflation rates.  Such indices are then aggregated into the 10 main RPI groups.  Apart from the inflation rate, these indices are also used to calculate the Cost of Living Adjustment (COLA).  The RPI is also regulated by Act XXIII/1979 (Chapter 158 Article 13 of the Laws of Malta).

Methodological description

Data for the RPI is compiled from price readings which are gathered every month from various outlets across Malta and Gozo, by a team of price collectors.  Besides this, prices for certain services are also collected by means of mail surveys, administrative data sources, telephone surveys, and online sources.  The RPI captures private households only whereas the Harmonised Index of Consumer Prices (HICP) covers private households, institutional households (such as retirement homes) and foreign visitors to Malta. 

The basket of consumption items considered for the RPI is reviewed periodically, in line with the Household Budgetary Survey (HBS), during which information of household consumption is collected over a 12-month period in order to obtain an estimate of the average household expenditure.  The information collected through the HBS exercise is then further supplemented by additional data sources to get to the final RPI weights.

The RPI is a fixed base index with weights periodically updated in line with the HBS.  On the other hand, the HICP is a chain-linked index with the weights reviewed on an annual basis.  Unlike the RPI where the sample of goods and services changes every time the weights are updated, newly significant goods and services can be introduced in the HICP framework on an annual basis.

Other measures produced are the inflation rate, percentage change on a monthly and annual basis, impact on inflation, and twelve-month moving average rate. 

Accuracy and reliability of data

Information on the accuracy and reliability of data can be viewed in a dedicated ESMS metadata report available on the NSO’s metadata website.  Moreover, data pertaining to the RPI is scrutinized by the RPI board prior to publication. 

Timeliness and punctuality of data

Data for the RPI is published in a news release on a monthly basis.  Data pertaining to a particular month is published in the subsequent month.  These are accessible on the NSO website and are published on the pre-established date, as scheduled in the Advance Release Calendar which can be viewed also on the NSO website. 

Accessibility and clarity of data

RPI data can be accessed from the NSO website via the StatDB.  An ESMS metadata report is also produced at a national level and is made available on the NSO metadata website.

Coherence and comparability/consistency of data

The current RPI series is published in accordance to the reference base December 2016.  RPI data is comparable over time; however, it has never been revised since this is not possible for the RPI.  Any improvements that are implemented to the method for compiling the RPI have minimal impacts on the overall RPI.  Comparison of RPI data to that of other countries is not possible since the RPI is only compiled for national purposes.   


Other Documents Date
The RPI and HICP Manual May 2008
Inflation Calculator News releases calendar Request for Information NACE Code queries
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