DRG Crosswalk

Convert APR-DRG to MS-DRG (federal standard) for national comparability.

Walkthrough

APR-DRG 302 → MS-DRG 469/470

Input: NY hospital reports rates for APR-DRG 302 across four severity of illness (SOI) levels: SOI 1 = \$5,000, SOI 2 = \$8,000, SOI 3 = \$12,000, SOI 4 = \$20,000.

Crosswalk: APR-DRG 302 maps to MS-DRG 469 and MS-DRG 470 via the CMS crosswalk table.

Average: (\$5,000 + \$8,000 + \$12,000 + \$20,000) / 4 = \$11,250

Output: MS-DRG 469 = \$11,250, MS-DRG 470 = \$11,250. Original APR-DRG billing codes are preserved in original_billing_codes.

Crosswalked rate: MS-DRG 470 = $11,250. Known bias: 3–15% higher than native MS-DRG due to SOI averaging.

Known bias: SOI averaging inflates crosswalked rates

Averaging across severity levels inflates the crosswalked rate by 3–15% compared to native MS-DRG rates. This is accepted because APR-DRG data would otherwise be unusable for national comparison — the alternative is discarding all APR-DRG rates entirely.