42 CFR § 412.517 - Revision of LTC-DRG group classifications and weighting factors.
(a) CMS adjusts the classifications and weighting factors annually to reflect changes in—
(1) Treatment patterns;
(2) Technology;
(3) Number of discharges; and
(4) Other factors affecting the relative use of hospital resources.
(b) Beginning in FY 2008, the annual changes to the LTC–DRG classifications and recalibration of the weighting factors described in paragraph (a) of this section are made in a budget neutral manner such that estimated aggregate LTCH PPS payments are not affected.
(c) Beginning in FY 2016, the annual recalibration of the weighting factors described in paragraph (a) of this section is determined using long-term care hospital discharges described in § 412.522(a)(2) (or that would have been described in such section had the application of the site neutral payment rate been in effect at the time of the discharge).