These notes discuss the sources of data used in creating the TBI surveillance system, case definition, data limitations, and procedures for case ascertainment.
Deaths can occur among the hospitalized cases.
The remaining records were classified as TBI-related hospitalized fatalities. The matching variables used in this process were Soundex of last name, name, date of birth, residence code and gender. These hospitalized fatal TBI records have information recorded on both the UB and death file to allow some comparisons of demographic and diagnostic variables reported from two independent sources of information. The MCD and SCD files for the calendar year 1997 were merged using the death certificate number. TBI-related mortality cases were then identified from one or more of the nature of injury codes listed in the merged file using the TBI case definition.