Tables 1 and 2 below are drawn from the article by Bunn P., Ellis C., (2012), "Examining the behaviour of individual UK consumer prices", The Economic Journal, 122, 558, F35 - F55 (the article is available on Moodle). The aim of the research is to investigate the frequency with which UK consumer prices change. In order to carry out their investigation the researchers analyse the behaviour of individual UK prices using the data that are used in the construction of the UK CPI and using a database of supermarket prices collected from scanner data.

Frequency of Consumer Price Changes Percentage of Implied duration Price measure Sample prices changing between price changes Monthly Consumer Price Index 1996-2006 19% a month 5.3 months (CPI) microdata CPI goods 1996-2006 24% a month 4.2 months CPI services 1996-2006 9% a month 11.1 months CPI excluding promotions 1996-2006 15% a month 6.7 months Weekly supermarket data February 2005-February 2008 60% a week 1.7 weeks Excluding fresh products February 2005-February 2008 40% a week 2.5 weeks Excluding fresh products and February 2005-February 2008 27% a week 3.7 weeks price reversals Notes. Monthly CPI microdata are locally-collected data only. All figures are weighted by sales values. Sources. CPI and Nielsen microdata.Food and Non-Alcoholic Beverages Alcoholic Beverages and Tobacco Energy Goods Non-Energy Industrial Goods Housing Services Transport and Travel Services Communication Recreational and Personal Services Miscellaneous Services 0 10 20 30 40 50 6O 70 % Fig. 2. Percentage of UK Consumer Prices That Change Each Month