EMS Data Resources & Documents

NEMSIS

NEMSIS Data Dictionaries
The NEMSIS data dictionary was developed through a collaborative effort with the EMS industry including: web-based reviews, public comment periods, focus groups, industry dialogue, topic focused projects, and consensus.

• v3.4.0 Build 200910 (September 2020)
  
• v3.5.0 Build 230317 Critical Patch 4 (March 2023)
• v3.5.1 Build 250115 (January 2025)

Data Definitions

• Extended Data Definitions, NEMSIS Version 3.5.0. (May 2024) Represents the continued effort of defining field values which started with NEMSIS v2.2.1 and supports the development, standardization, and improvement of state, territory and national EMS data systems.
  
• EMS Encounter Time Interval Definitions. (June 2024) Defines the duration between key operational milestones during a response. By tracking the physical movements of both patient and crew, these intervals help agencies evaluate and optimize EMS performance.

Guidance Materials

• Blood Product Administration Documentation–Best Practice Guidance (revised December 2025). Provides states with a standardized method for documenting blood product usage, which will facilitate improved data analysis.
• Artificial Intelligence Use In EMS (December 2025). Outlines the benefits, risks, and critical considerations EMS leaders must evaluate to ensure responsible, secure, and ethical use of AI technologies within their operations.
• Requesting EMS Data Across States–Key Considerations and Guidance (December 2025). Requesting EMS data from multiple states can support vital work in system improvement, public health, research, and commercial innovation. However, EMS data access is governed by state-specific policies, privacy standards, and legal requirements. This document offers essential guidance to help you navigate state EMS data requests responsibly and effectively.