Once a title has had estimates published on a 12 or 24-month base, the period on which subsequent estimates are based may change, as follows:
•From 24 to 12 months
Estimates for a title on a 24-month base will be transferred to a 12-month base if the title achieves at least 175 unweighted AIR participants in the most recent 12-month period ending in June.
•From 12 to 6 months
Estimates for a title on a 12-month base will also be released on a 6-month base if the title achieves 175 unweighted AIR participants in each of two consecutive 6-month periods, this 12-month period ending in June. Estimates on a 12-month base will continue to be released.
In all cases the media list will be reviewed each year when data to June becomes available, and the above changes will be made where appropriate.
