We thank Mr Foo Sing Kheng for his feedback (Inflation data should take into account shrinkflation, March 30).

The consumer price index (CPI) measures average changes in the prices of a basket of consumer goods and services commonly purchased by households.

In compiling the CPI, the Singapore Department of Statistics accounts for changes in quantity, where possible, by adjusting the price data of the items tracked in the CPI basket on the basis of a fixed unit of measurement.

For example, if the packaging quantity of an item in the CPI basket changes from 200g to 180g but the price is unchanged at $6, the item’s price will be computed as having risen from $3 per 100g to $3.33 per 100g in the CPI. 

For food items where certain ingredients were previously provided at no charge, but are now charged separately, the additional charge will generally be computed as an increase in the price of the food item. 

For more information on CPI compilation, please refer to the SingStat website, go.gov.sg/latestdatapriceindices

Hya Ting Yu
Senior Assistant Director, Prices,
Department of Statistics