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Table 3 High cardinality of combinations of name and date of birth

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

Identifier

Cardinality

Average NHS numbers per identifier

National Health Service Number

1066339

1

Date of birth

35694

29.87

Surname, complete forename

829650

1.285

Surname, first letter of forename, date of birth

1065027

1.001316

Surname, first three letters of forename, date of birth

1066184

1.000234

Surname, complete forename, date of birth

1066519

1.000090

  1. For a set of complete identifiers from one data source (PAS), we show the cardinality (number of discrete values) for each of a series of possible identifiers, and average number of NHS numbers per identifier. This cardinality of NHS number and combinations of name and date of birth are similar.