Large administrative databases provide powerful opportunities for examining the epidemiology of injury. The National Coronial Information System (NCIS) contains Coronial data from Australia and New Zealand (NZ); however, only closed cases are stored for NZ. This paper examines the completeness of NZ data within the NCIS and its impact upon the validity and utility of this database. A retrospective review of the capture of NZ cases of quad-related fatalities held in the NCIS was undertaken by identifying outstanding Coronial cases held on the NZ Coronial Management System (primary source of NZ Coronial data). NZ data held on the NCIS database were incomplete due to the non-capture of closed cases and the unavailability of open cases. Improvements to the information provided on the NCIS about the completeness of NZ data are needed to improve the validity of NCIS-derived findings and the overall utility of the NCIS for research.