Data Item	Weighted Percent of Records With No Discrepancy
	Medicare	NHDS
Admission Date	99.6	99.6
Discharge Date	99.2	97.8
Principal Diagnosis (4 digits)	75.8	71.7
Principal Procedure1	88.4	88.1

Source: From IOM, 1980, p. D3; and IOM, 1977, p. 108.

¹The percent of records with no discrepancy on principal procedure includes cases without surgery. If the analysis were restricted to cases with surgery, the percent of cases with no discrepancy would decline.