- Changes in Cause of Death Coding in 1999 - The International Classification of Diseases (ICD) is a product of the World Health Organization and is used worldwide. The United States adopted the Tenth Revision of the ICD (ICD-10) in 1999. The revision not only effects the codes and names assigned to causes of death, it also effects the rules for selecting the underlying cause of death and the grouping of causes for tabulation and selection of leading causes of death. The changes are such that there is no direct mapping from one system to the other. Because of this, there appear to be dramatic increases or decreases in the numbers of deaths due to certain causes between 1998 and 1999. The user is cautioned against attempting analyses that involve combining or comparing data produced under the two different coding systems (see below for more information on how to make comparisons between the two systems). For additional information on the Tenth Revision of the International Classification of Diseases (ICD-10), see the National Center for Health Statistics publications Comparability of Cause of Death Between ICD-9 and ICD-10 Preliminary Estimates: and Deaths: Final Data for 1999.
- Comparability Ratios - To make deaths coded under the ninth revision (ICD-9) comparable to data coded under ICD-10, the National Center for Health Statistics (NCHS) computed preliminary comparability ratios for 130 selected causes of infant death. When applied to deaths coded in accordance with ICD-9, the comparability ratios allow for trend analysis by eliminating differences due solely to the change in ICD. The data used to prepare these comparability ratios were national level and did not take into account differences due to age, race, sex, or geography. More detailed comparability ratios are currently under development that will reflect the effect of age, race, sex, and geography. Note that these comparability ratios are only reliable for use with 1994-1998 data. Use with data from earlier years may produce erroneous results. Comparability ratios needed for use with the data in NJSHAD are available in New Jersey Health Statistics, 1999.