Death data are based on a subset of variables collected on the Texas Certificate of Death.  Death data are available in two modules, one for the years 1990 through 1998 and one for the years 1999 through 2010.   Two modules are necessary for death statistics because deaths occurring during 1990 through 1998 were coded using ICD-9 while deaths occurring since 1999 are coded using ICD-10.

• Changes in Cause of Death Coding for 1999 and later - for years prior to 1999, cause of death was coded according the Ninth Revision of  the International Classification of Diseases (ICD-9).  The Tenth Revision (ICD-10) was implemented for years 1999 and onward.  ICD-10 represents a substantial change from the ICD-9.  The number of disease categories has expanded from ICD-9 and category names, coding rules and standard tabulation lists have changed such that there is no direct mapping from one system to the other.  NCHS is developing methods to facilitate comparisons between death statistics coded under ICD-9 and those coded under ICD-10 (comparability ratios).  For the present, Texas Health Data provides mortality statistics for years 1999 and onward in a separate module.  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 comparisons between the two coding systems).

 
• Cause of Death Selections - The choices for the cause of death available for both the ICD-9 and the ICD-10 systems are divided into three levels that are based on predefined lists developed by NCHS for the tabulation and dissemination of data.  For years 1999 and onward, the causes of death listed on the input screen comprise the first level and are the categories used to determine the leading causes of death.  The second level is more detailed and is based on the NCHS List of 113 Selected Causes of Death.  The third level  is a modified version of the NCHS List of 358 Selected Causes of Death.  In order to obtain information from the more detailed second or third  levels, the user must first select the broader category in the first level and then “drill down” to the second level and third level.  In some cases, the level of detail does not change from the first level to the third level. In other cases the level of detail does not change from level one to level two but is more detailed in level three.  A detailed searchable list of the three levels of data based on ICD-10 provides more information on the drill-downs.


  For pre-1999 statistics, the drill-down lists are also based on modified NCHS tabulations, but  with less detail.
 

• Comparability Ratios - NCHS has developed comparability ratios to support comparisons between ICD-9 and ICD-10.  Comparability ratios were derived by double-coding 1996 deaths using both systems and calculating the ratio of the number of deaths based on ICD-10 to the number based on ICD-9, for each specific cause.  This analysis was carried out for the NCHS list of 113 causes of death. The data used were at the national level and did not take into account differences due to age, race or geography.  More detailed comparability ratios are currently under development that do reflect the effect of age, race and geography.  A report comparing the coding systems and providing comparability ratios is provided at http://www.cdc.gov/nchs/data/nvsr/nvsr49/nvsr49_02.pdf

 
• Age Adjustment - age adjusted death rates provide unbiased comparisons that are not influenced by differences in age distribution in subject populations.  The standard used  is the US 2000 standard population.  More information on age adjusting is available at http://www.cdc.gov/nchs/data/statnt/statnt06rv.pdf and on the choice of standard population at http://www.cdc.gov/nchs/data/statnt/statnt20.pdf
  Note: Age adjusted rates retrieved from this system after December 8, 2008 will be slightly different from those retrieved previously, because of a change in methodology. The differences will be small.

 
• New Death Certificate for 2006 - beginning in 2006, a new Certificate of Death Form is being used in Texas. Data users are cautioned that some data items might not be directly comparable with previous years.

Last Updated May 15th, 2013