Table 7

Example showing the eight combinations when we have two hierarchical quasi-identifiers where we disclose all of their levels

Combination ID

PROV_XXX

AGE_GROUP

GENDER_CODE

MRDx

CMG_CODE

DIAG_BLOCK

DIAG_CHAPTER

CCI_CODE

SHORT_CCI

2a

X

X

X

X

X

2b

X

X

X

X

X

2c

X

X

X

X

X

2d

X

X

X

X

X

2e

X

X

X

X

X

2f

X

X

X

X

X

2g

X

X

X

X

X

2h

X

X

X

X

X

Emam et al. BMC Medical Informatics and Decision Making 2011 11:53   doi:10.1186/1472-6947-11-53