Impacts of COVID-19 on methodology for the December 2020 quarter CPI

Impacts of COVID-19 on methodology for the December 2020 quarter CPI

15 January 2021

This paper summarises the impacts of COVID-19 on the methodology used for the December 2020 quarter consumers price index (CPI) following on from our September 2020 quarter paper (see Impacts of COVID-19 on the methodology used for the September 2020 quarter CPI).

We focus on collection issues, imputation to replace missing prices, reintroducing prices for missing items, and reweighting the CPI basket.

COVID-19 has created some unprecedented data collection and methodological challenges for the CPI in 2020. In the December 2020 quarter in-person collection of data was not interrupted by COVID-19 lockdowns as New Zealand was under alert level 1. This compares with both the June and September 2020 quarters where in-person collection of data from stores ceased for a while, which meant contacting business respondents was more difficult. We’re also reintroducing the prices for one international airfare route as more people are starting to fly as travel restrictions ease.

Visit our website to read this paper: Impacts of COVID-19 on methodology for the December 2020 quarter CPI