Spelling errors are common on death certificates; therefore, the death records were first processed through a spell checker to identify misspellings. Although the UMLS SL has a spell suggestion tool called GSPELL [35] [36] [37] , we decided not to use it and chose to utilize ASPELL [38] . Our motivation for this decision was based upon an evaluation which showed ASPELL outperforming GSPELL; ASPELL performed better on three areas of performance which were (2) whether the correct word was ranked in the top ten; and (3) whether the correct word was found at all [35] . PERL (www.perl.org), a high-level computer programming language that aids in the manipulation and processing of large volume of text data was then used to prepare the cause of death free text for NLP. The preprocessing also involved the removal of non-ASCII characters; this was a required technical step for MetaMap processing.