Data about national notifiable diseases and conditions are collected by reporting jurisdictions through their reportable disease surveillance programs. Each reporting jurisdiction determines how to manage their priority health issues and resources. Therefore, each reporting jurisdiction determines whether a surveillance system for a given notifiable disease in their state or territory should be active or passive in nature, and state-wide or localized to a specific region of the state or territory. Because resources and priorities change over time, the attributes of a surveillance system for a given disease or condition are also subject to change over time. The nature and characteristics of each reporting jurisdiction’s surveillance system may impact the interpretation of an NNDSS-based data analysis.