This project links data on acute inpatient hospitalizations from the Canadian Discharge Abstract Database (DAD) with data on income and employment from various taxation- and employment-based administrative files. The goal was to create a linked database that will support research on the labour market and financial outcomes experienced by individuals and families following acute illness requiring hospitalization.
Data from the 1999/00 to 2014/15 Discharge Abstract Database (DAD) were linked to the 1981-2013/14 T1 Tax filer data and the Canadian Child Tax Benefit data. We sought to create a unique association between Health Insurance Numbers (HIN) available in the DAD and Social Insurance Numbers (SIN) available in the tax data by using variables common to both data sets - date of birth, postal code and sex. Both transactional data sets were ``individualized'' such that unique combinations of the linkage variables were identified and eligible for linkage. The linkage was conducted using deterministic methods.
Approximately 97% of combinations involving date of birth, postal code and sex in the hospitalization data were uniquely related to a single valid HIN (n=18.8 million). Similarly, approximately 96% of the keys on the Tax data file were associated with a unique person. Approximately 86% of HINs were associated with a unique identifier in the tax file and these HINs account for approximately 83% of the hospital records. The linkage was consistent over time, with linkage rates between 85% and 88% of HINs for all years. Some variation in linkage rates were observed by jurisdiction and by age. (Error estimates to be reported)
This project has created a unique linked database that will support research on the economic consequences of `health shocks' for individuals and their families, and the implications for income, labour and health policies. This database represents a new and unique resource that will fill an important national data gap, and enable a wide range of relevant research.