The MDS is also used in establishing Medicare skilled nursing facility (SNF) payment rates. Beginning in 1998, CMS began paying Medicare SNFs prospective payment rates adjusted using data from the MDS. CMS permits the use of yet another MDS form in calculating Medicare PPS payment rates. The MDS payment form is required to be completed at multiple points during a Medicare SNF stay. In addition, a number of States also use an MDS form to adjust Medicaid nursing facility payment rates.