MetaMap was used to convert the electronic death records to coded descriptions appropriate for the rule based system. MetaMap [34] , developed by the National Library of Medicine (NLM), is useful in identifying biomedical concepts from free-form textual input and maps them into concepts from the Unified Medical Language System (UMLS) Metathesaurus [34, 39] . MetaMap works by breaking the inputted text into words or phrases, map them to standard terms, and then match the terms to concepts in the Unified Medical Language System (UMLS) [40] . For each matched phrase, MetaMap classifies it into a semantic type then returns the concept unique identifier (CUI) and the mapping options which are ranked according to the strength of the mapping. output from MetaMap. Text bolded in the output from NLP represent the code and its corresponding phrase.