Skip to main content

Table 2 The Quasi-identifiers

From: De-identifying a public use microdata file from the Canadian national discharge abstract database

Quasi-identifiers Coding # Categories
PROV_XXX Province/region. Quebec data is not included in the DAD.  
PROV_ALL The territories are grouped into one category + 9 provinces 10
PROV_REGION The country is divided into three regions (West, Central, and East), where Central consists of Ontario. 4
TOTAL_LOS_XXX Total Length of stay  
TOTAL_LOS_DAYS Days up to 1 week, then in weeks up to 6 months, and top coded at 6 months + 31
TOTAL_LOS_WEEKS Weeks up to 6 months everything longer than that is top-coded into a single category 25
AGE_GROUP Five year intervals and top coded at 90 years 20
GENDER_CODE unchanged 51
Different levels of coding detail of the most responsible diagnosis code. 8967
CMG_CODE These identify Case Mix Groups (CMGs), which are groups of patients with similar clinical and cost characteristics. They are based on most responsible diagnosis (MRDx) and other diagnosis and intervention information. 545
Different levels of coding detail of the principle intervention. Approximately 46% of the records had no interventions. 8780
  1. This table displays the quasi-identifiers that were being analyzed and the number of response categories. There are two versions of the province and total length of stay fields as they represent different levels of detail.
  2. 1 Five gender codes are used in the DAD: F-female, M-male, O-other (trans-sexual or hermaphrodite, U-undifferentiated(stillbirths only), and Z-missing.