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Table 1 Definitions of test and performance characteristics

From: Technical evaluation of methods for identifying chemotherapy-induced febrile neutropenia in healthcare claims databases

  Gold standard  
   Yes No  
  Yes X Y  
  No Z K  
Test/Performance Characteristic   Definition Explanation
 Patient Classification, %    
  True-Positive   X / (No. of Patients) × 100%  
  False-Positive   Y / (No. of Patients) × 100%  
  True-Negative   K / (No. of Patients) × 100%  
  False-Negative   Z / (No. of Patients) × 100%  
 Sensitivity, %   X / (X+Z) × 100% % of FN hospitalizations correctly identified by claims-based definition
 Specificity, %   K / (Y+K) × 100% % of non-FN hospitalizations correctly identified by claims-based definition
 Positive Predictive Value (PPV), %   X / (X+Y) × 100% % of hosp. identified as FN hosp. by claims-based definition that were true-positives
 Negative Predictive Value (NPV), %   K / (Z+K) × 100% % of hosp. identified as non-FN hosp. by claims-based definition that were true-negatives
 Accuracy, %   (X+K) / (No. of Patients) × 100% % of all hospitalizations that were true-positives and true-negatives
 Likelihood ratio positive (LR+)   [X/(X+Z)] / [1-K/(Y+K)] Odds of hosp. being an FN hosp. when claims-based algorithm is positive
 Likelihood ratio negative (LR-)   [1-X/(X+Z)] / [K/(Y+K)] Odds of hosp. being a non-FN hosp. when claims-based algorithm is negative
  1. FN: febrile neutropenia.