HDB resale price index

How the index is calculated

The source notes that the series is based on quarterly average resale prices by date of registration. Values through 3Q2014 used a stratification method; from 4Q2014 onward HDB uses a stratified hedonic regression method.

Index vs median transaction price

The index aims to measure underlying market movement. The median is the middle registered sale and can shift when different types of flats transact. HDBLens shows both but never labels its calculated median as the official index.