Among the commodity groups, Alcoholic Beverages and Tobacco posted the highest CPI in December 2020 at 246.0, followed by Housing, Water, Electricity, Gas, and Other Fuels at 143.9, and Health at 134.8. On the other hand, Recreation and Culture at 114.1, Transport at 113.4, and Communication at 106.5 were the three commodity groups with the lowest CPI recorded in the month of December 2020. (See Figure 2)
Consumer Price Index (CPI) – The CPI is an indicator of the changes in the average retail prices of a fixed basket of goods and services commonly purchased by households relative to a base year.
Used of CPI – CPI is most widely used in the calculation of the inflation rate and purchasing power of peso. It is a major statistical series used for economic analysis and as a monitoring indicator of government economic policy.
Computation of CPI – The computation of the CPI involves consideration of the following important points:
- Base Period – The reference data or base period is the benchmark or reference date or period at which the index is taken as equal to100.
- Market Basket – A sample of the thousands of varieties of goods purchased for consumption and services availed by the households in the country selected to represent the composite price behavior of all goods and services purchased by consumers.
- Weighing System – The weighing pattern uses the expenditures on various consumer items purchased by households as a proportion to total expenditure.
- Formula – The formula used in computing the CPI is the weighted arithmetic mean of price relatives, the Laspeyre’s formula with a fixed base year period (2012) weights.
- Geographic Coverage – CPI values are computed at the national, regional, and provincial levels, and for selected cities.
Inflation Rate (IR) – is the rate of change of the CPI expressed in percent. Inflation is interpreted in terms of declining purchasing power of peso.
Purchasing Power of Peso (PPP) – shows how much the peso in the base period is worth in the current period. It is computed as the reciprocal of the CPI for the period under review multiplied by 100.