Evaluate Possible Explanations to Identify the Source of the Outbreak

Last Updated: March 2022

To evaluate the possible explanations generated, it is best to provide descriptive statistics stratified by key variables (e.g., demographics). Some examples are: 

• Characteristics of Fentanyl Overdose – Massachusetts, 2014-2016 
• Increases in Fentanyl-Related Overdose Deaths — Florida and Ohio, 2013–2015 
• Deaths Involving Fentanyl, Fentanyl Analogs, and U-47700 — 10 States, July–December 2016. 

Risk factors and associations that have been identified in the data should be tested for statistical significance. However, a lack of statistical significance does not indicate that risk factors are not important. When evaluating an outbreak, decide if more formal studies might be necessary (e.g., case control or cohort studies). There are many data sources that might be relevant to the outbreak and should be considered. Analyze multiple data sources to investigate the cause of the outbreak. Consider these data sources for analysis:

• Medical record abstraction
• Site visits 
• ED data