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Table 3 Suggested linkage cycles/iterations

From: Validation of de-identified record linkage to ascertain hospital admissions in a cohort study

 

Linkage Variables

Records

linked

Records

remaining

Iteration

Medicare8 1 + Medsuf1 2 group

 

1-4

Medicare8+Medsuf1+Yearbirth+Monthbirth+Daybirth+Sex+COB+ Postcodes1-4

1594

406

5-16

Repeat steps 1-4 using 3 different variations of Medsuf1

8

398

17

Repeat step 1 dropping postcode

23

375

18-21

Repeat steps 1-4 dropping COB

7

368

22-25

Repeat steps 1-4 dropping sex

1

367

26-29

Repeat steps 1-4 dropping day of birth

19

348

30-33

Repeat steps 1-4 dropping month of birth

2

346

34-37

Repeat steps 1-4 dropping year of birth

17

329

38-100

Repeat steps 5-16, dropping 1 variable

0

329

101-141

Repeat steps 1-4 dropping two demographic variables

4

325

 

Medicare8 group

142-145

Medicare8+Yearbirth+Monthbirth+Daybirth+Sex+COB+ Postcodes 1-4

24

301

146-166

Repeat steps 142-145 dropping 1 variable

2

299

 

Medsuf1 Group

167-170

Medsuf1+Yearbirth+Monthbirth+Daybirth+Sex+COB+ Postcodes 1-4

39

260

Total records linked = 1740/2000 = 87%

  1. 1 First 8 digits of the Medicare number; 2 First 3 letters of the first name