42 C.F.R. § 414.1215
Performance and payment adjustment periods for the value-based payment modifier
(a) The performance period is calendar year 2013 for value-based payment modifier adjustments made in the calendar year 2015 payment adjustment period.
(b) The performance period is calendar year 2014 for value-based payment modifier adjustments made in the calendar year 2016 payment adjustment period.
(c) The performance period is calendar year 2015 for value-based payment modifier adjustments made in the calendar year 2017 payment adjustment period.
(d) The performance period is calendar year 2016 for value-based payment modifier adjustments made in the calendar year 2018 payment adjustment period.