Provisional Counts of Overdose Deaths Can Be Misleading

The federal Centers for Disease Control reported on December 21, 2017, that there had been a total of 63,600 deaths attributed to drug overdose in the US in 2016. Based on data available for analysis on Oct. 1, 2017, the CDC's provisional count of drug overdose deaths in the US for the 12-month period ending in December 2016 had been 71,135. The difference is attributed to data quality: provisional counts are by definition incomplete, which means they can be misleading.

The CDC compiles and publishes official data on annual causes of death in the United States. Demand for data on drug overdose deaths, and on drug overdoses generally, is so great that the CDC is now making raw data on these subjects available to the public. Those data are provisional, not final, and so can be misleading. Several caveats that must be understood before examining the numbers. According to the CDC:

"Provisional counts are often incomplete and causes of death may be pending investigation (see table Notes). Data quality measures, such as percent completeness in overall death reporting and percentage of deaths pending investigation, are included to aid interpretation of provisional data, because both data completeness and the percentage of records pending investigation are related to the accuracy of provisional counts (see Technical Notes). Provisional data are based on available records that meet certain data quality criteria at the time of analysis and may not include all deaths that occurred during a given time period. Therefore, they should not be considered comparable with final data and are subject to change. Reporting of specific drugs and drug classes varies by jurisdiction, and comparisons across selected states should not be made (see Technical Notes)."


Hedegaard H, Warner M, Miniño AM. Drug overdose deaths in the United States, 1999–2016. NCHS Data Brief, no 294. Hyattsville, MD: National Center for Health Statistics. 2017.
"Provisional Drug Overdose Death Counts," U.S. Centers for Disease Control, Atlanta, GA, based on data available for analysis on Oct. 1, 2017, last accessed Oct. 19, 2017 at