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Table 1 Identifiers and Record linkage operation

From: An efficient record linkage scheme using graphical analysis for identifier error detection

Start cluster id New cluster id NHS number hospital number Surname Forename sex date of birth (ddmmyyyy) frequency of occurrence
1 1 NULL 4496644 WILSON DAVID M 14061940 3
2 2 5170231111 NULL WILSON DAVID M 01051939 1
3 3 3319004037 4118890 WILSON DAVID M 20011969 2
5 3 3319004037 NULL WILSON DAVID M 20011969 2
6 6 NULL 4118890 WILSON DAVID M 20011969 1
  1. An example of identifiers provided for patients with forename and surname 'David Wilson'. The details have been changed to protect patient confidentiality. Null fields indicate there was no information provided in that field.
  2. One cycle of the record linkage is illustrated. Consider each combination of identifiers to belong to its own, discrete cluster, identified by a cluster identifier (Start cluster id). For all sets in which at least one member shares an NHS number identifier with a different set, combine these sets into a single set (New Cluster ID). The operation proceeds for all identifiers.