Mortality Data Sources

How Mortality Data Are Collected

Cancer mortality statistics are based on information from all death certificates filed in the 50 states, the District of Columbia, and Puerto Rico and processed by CDC’s National Center for Health Statistics (NCHS) National Vital Statistics System (NVSS). The cancer mortality data were compiled in accordance with World Health Organization (WHO) regulations, which specify that member nations classify and code causes of death in accordance with the current revision of the International Classification of Diseases (ICD). Effective with deaths that occurred in 1999, the United States began using the tenth revision of this classification (ICD–10).1 2

Rules for coding the cause(s) of death may require modification when evidence suggests that such modifications will improve the quality of cause-of-death data. Before 1999, such modifications were made only when a new revision of the ICD was implemented. A process for updating the ICD that allows for mid-revision changes was introduced with ICD-10. Minor changes may be implemented every year, while major changes may be implemented every three years. These updates do not have a significant effect on the data in the U.S. Cancer Statistics Data Visualizations tool.

The ICD not only details disease classification but also provides definitions, tabulation lists, the format of the death certificate, and the rules for coding cause of death. Cause-of-death data presented in the U.S. Cancer Statistics Data Visualizations tool were coded by procedures outlined in annual issues of the NCHS Instruction Manuals.

Underlying Cause of Death

In the U.S. Cancer Statistics Data Visualizations tool, tabulations of cause-of-death statistics are based solely on the underlying cause of death, which is defined by WHO as “the disease or injury that initiated the train of events leading directly to death, or the circumstances of the accident or violence that produced the fatal injury.”1 The underlying cause of death is selected from the conditions entered by the physician in the cause-of-death section of the death certificate. Generally, more medical information is reported on death certificates than is reflected directly in the underlying cause of death.3 4

Cancer Site Groups

For consistency with the data on cancer incidence, the cancer sites in mortality data were grouped according to the revised SEER recodes dated March 1, 2018. Because NCHS uses different groupings for some sites, the death rates in this report may differ slightly from those published by NCHS. In addition, under the ICD, there are differences in mortality and incidence coding. For example, in ICD-10, mesothelioma deaths are coded by anatomic site whereas in ICD-O-3, mesothelioma incidence is coded by morphology, regardless of anatomic site.

Death Rates for Kaposi Sarcoma

Because the vast majority of Kaposi sarcoma (KS) cases have developed in association with human immunodeficiency virus (HIV) infection and acquired immunodeficiency syndrome (AIDS), HIV/AIDS is listed as the underlying cause of death. Therefore, KS death rates were not included.

Mortality Data Submission Process

Unlike incidence data, mortality data for a calendar year are not updated after the final data file is released. All states, the District of Columbia, and Puerto Rico submitted all of their 2020 mortality data in electronic data files to NCHS. Mortality data for the entire United States refer to deaths that occurred within the United States; data for geographic areas are by the decedent’s place of residence.


  1. Xu J, Murphy SL, Kochanek KD, Arias E. Deaths: Final data for 2019 [PDF-2.5MB] National Vital Statistics Reports 2021;70(8).
  2. World Health Organization. International Statistical Classification of Diseases and Related Health Problems, Tenth Revision. Geneva, Switzerland: World Health Organization; 1992.
  3. Chamblee RF, Evans MC. TRANSAX: the NCHS system for producing multiple cause-of-death statistics, 1968–78. Vital and Health Statistics, Series 1 1986;(20):1–83.
  4. Israel RA, Rosenberg HM, Curtin LR. Analytical potential for multiple cause-of-death data. American Journal of Epidemiology 1986;124(2):161–179.