External validation of a claims-based algorithm for classifying kidney-cancer surgeries

Table 1 Agreement between claims algorithm and SEER data for receipt of cancer-directed surgery among patients with kidney cancer

		RECEIPT OF SURGERY BASED ON MEDICARE CLAIMS
		No	Yes	Total
RECEIPT OF SURGERY BASED ON SEER CANCER-DIRECTED SURGERY VARIABLE	No	647	94	741
	Yes	385	5389	5774
	Total	1032	5483	6515
Observed agreement = 92.6%
Kappa = 0.69 (0.66–0.71)
Sensitivity ^† = 93.3% (92.7%–94.0%)
Specificity ^† = 87.3% (84.7%–89.6%)
Positive Predictive Value ^† = 98.3% (97.9%–98.6%)
Negative Predictive Value ^† = 62.7% (59.7%–65.7%)

† Calculations based on SEER cancer-directed surgery variable as the reference-standard

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