TRIR and DART Rate are the two most widely used lagging safety metrics in the United States, yet many EHS professionals are unsure when to use one versus the other. Both rates share the same formula structure and use the same 200,000-hour normalization factor, but they measure different things. Understanding what each metric tells you, and what it does not, is essential for meaningful safety performance measurement. This guide explains both rates, introduces the Severity Rate as a third dimension, and shows how they work together.
TRIR: Total Recordable Incident Rate
What TRIR Measures
TRIR counts all OSHA recordable incidents per 100 full-time employees. This includes every injury or illness that results in death, days away from work, restricted work or job transfer, medical treatment beyond first aid, loss of consciousness, or a significant diagnosis. TRIR is the broadest safety metric and captures the total volume of recordable events.
Calculate yours instantly with our free TRIR Calculator.
When TRIR Is Used
- Contractor prequalification - Most owner-operators require TRIR disclosure. ISNetworld, Avetta, and similar platforms collect TRIR data.
- Internal benchmarking - Comparing facility-to-facility or year-over-year safety performance
- Insurance underwriting - Carriers use TRIR to price workers' compensation and general liability coverage
- BLS industry comparison - The Bureau of Labor Statistics publishes TRIR averages by NAICS code, enabling industry benchmarking
DART Rate: Days Away, Restricted, or Transferred
What DART Measures
DART Rate counts only the subset of OSHA recordable incidents where the outcome is days away from work, restricted work activity, or transfer to another job. It excludes "other recordable" cases where the worker received medical treatment beyond first aid but was able to continue their normal job duties without restriction. DART therefore focuses on more serious incidents.
Calculate yours instantly with our free DART Rate Calculator. For a deeper dive into what constitutes a DART incident, see our DART Rate Guide.
When DART Is Used
- OSHA Site-Specific Targeting (SST) - OSHA uses DART rates from electronic 300A submissions to target establishments for programmed inspections
- Measuring injury severity - A high DART-to-TRIR ratio indicates most of your incidents are serious, not just minor recordables
- Workers' compensation analysis - DART incidents drive the majority of claims costs because they involve lost time
- Return-to-work program effectiveness - Tracking DART helps measure how well your organization manages restricted duty and return-to-work processes
The Key Differences
TRIR vs DART at a Glance
- Scope: TRIR includes all recordable incidents. DART includes only those with days away, restriction, or transfer.
- Relationship: DART is always less than or equal to TRIR. The gap between them represents "other recordable" cases (medical treatment only).
- Primary use: TRIR is the benchmark for overall safety performance. DART focuses on more serious outcomes.
- OSHA targeting: OSHA uses DART, not TRIR, for their SST inspection targeting program.
- Contractor prequalification: Most programs request TRIR. Some also request DART.
Severity Rate: The Third Dimension
What Severity Rate Adds
While TRIR counts how often incidents happen and DART counts how often serious incidents happen, neither measures how much work time is lost. That is where the Severity Rate comes in. Two companies can have identical DART Rates but very different Severity Rates if one company's incidents result in a few days of restricted work while the other's result in months of lost time.
Calculate yours with our free Severity Rate Calculator. Use all three metrics together for a complete safety picture: TRIR for incident frequency, DART for serious incident frequency, and Severity Rate for impact.
Using All Three Metrics Together
What the Patterns Tell You
- High TRIR, Low DART: You have many recordable incidents, but most are minor (medical treatment only). Focus on first-aid-level hazard controls and near miss prevention.
- High DART, High Severity: When serious incidents occur, they are very serious. Focus on high-energy hazard controls, engineering controls, and root cause analysis of your most impactful events.
- Declining TRIR, Stable DART: Your overall incident count is dropping, but the proportion of serious incidents is not improving. Your prevention efforts may be eliminating minor incidents but not addressing the higher-risk activities.
- All three improving: Your safety program is working. Continue current strategies, track leading indicators like near miss reports and inspection completion rates, and benchmark against industry averages.
Ecesis Incident Management Software
Incident Management
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Safety Inspections
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Employee Training
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Task Management
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Compliance Obligations
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Mobile EHS App
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