The National Health Data Dictionary (NHDD) provides national data standards for the health sector. This version (Version 16.1) reflects changes to data standards between May 2012 and the end of June 2013. Six national minimum data sets, 5 data set specifications, 61 data elements, 4 classification schemes and 5 glossary items have been added to the NHDD. Eighteen national minimum data sets, 15 data set specifications, 89 data elements, 6 classification schemes and 5 glossary items have been superseded or retired since the previous version of the NHDD (Version 16) was published.