Table 1

Linkage accuracy tool

Assigned link statusTrue match status
(pair from same individual)
(pair from different individuals)
LinkTrue match aFalse match b
Non-linkMissed match cTrue non-match d
  • Sensitivity (or recall)=a/(a+c); specificity=d/(b+d); positive predictive value (or precision)=a/(a+b); negative predictive value=d/(c+d). In practice, the number of non-matches will usually far outweigh the number of matches, and so the positive predictive value and sensitivity are more informative than the specificity and negative predictive value.