Incident and DART rate calculations
CHST written lesson, 11 min read. CHST Domain 3: Safety Program Development, Implementation, and Sustainment
AI-drafted from the cited rules and fact-checked against them. Study aid, not site-specific safety advice. The official rule controls.
What you'll learn
- State the incidence rate formula and explain the 200,000-hour base
- Identify which case outcomes count in the TRIR numerator
- Identify which cases count in the DART numerator
- Apply the day-counting rules for days away and restriction
- Calculate TRIR and DART and interpret them as cases per 100 full-time workers
What this lesson covers
This lesson shows how to turn a count of injuries and illnesses into a standardized rate, and which cases belong in the total recordable rate versus the narrower days-away, restricted and transfer rate. Rate questions are routine calculation items on the exam, and the same math drives year-end reporting and benchmarking on the job.
This lesson is included with a pass
Written lessons come with every CHST pass, along with the video lessons, the question bank, mocks and the tutor. $80 per exam or $143 for all three, for 180 days.