The Hamptons Monthly Lettings Index has been running since 2012. The index is a mix adjusted series, with rent and rental growth figures for each month based on a three-month rolling average. The most expensive decile of homes let are excluded to reduce volatility and the mix includes the most recently published government stock statistics.
The Hamptons Lettings Index uses data from the Countrywide Group to track changes to the cost of renting. The index is based on the 90,000 homes let and managed by Countrywide each year, adjusting for their location and type. It is based on achieved rather than advertised rents.