Total Case Incident Rate (TCIR)

This tool converts your raw injury and exposure numbers into normalized safety rates so you can compare performance across sites, shifts, or industries. The primary metric Total Case Incident Rate (TCIR), sometimes called TRIR, expresses the number of OSHA-recordable injuries and illnesses per 100 full-time workers on an annualized basis.

The same normalization is used to compute DART (Days Away, Restricted, or Transferred), Lost Time Injury Rate (LTIR), and Severity Rate (days lost per 100 employees).

How the math works

• TCIR / TRIR = (Number of OSHA recordable cases × 200,000) ÷ Total hours worked.
• DART Rate = (Number of DART cases × 200,000) ÷ Total hours worked.
• LTIR = (Number of lost-time cases × 200,000) ÷ Total hours worked.
• Severity Rate = (Total days away or lost × 200,000) ÷ Total hours worked.
  We use 200,000 hours as the base because it equals the annual hours worked by 100 full-time employees (100 employees × 40 hours/week × 50 working weeks/year) — this standardizes the metric so organizations of different sizes can be compared fairly.

What to include in “hours worked” and how to treat partial periods

Count every hour actually worked by your employees during the measurement period, including hours for temporary workers you supervise. Do not include paid but non-working hours such as vacation, bereavement, holidays, or sick leave. If precise hours are not available for salaried, commissioned, or per-mile workers, you may reasonably estimate hours based on scheduled hours or assume eight hours per workday.

For monthly calculations, replace 200,000 with 16,667 (the 1/12th equivalent) to normalize results to 100 full-time employees for a single month.

What makes an injury “OSHA recordable”?

An injury or illness must be recorded if it results in one or more of the following: death; days away from work; restricted work or transfer to another job; medical treatment beyond first aid; loss of consciousness; or a significant diagnosed condition confirmed by a health care professional.

How to interpret the results

A higher TCIR or DART indicates more incidents relative to workforce exposure but numbers don’t tell the whole story. Small employers with low total hours may see volatile rates caused by a single event, while large employers typically present smoother trends.

Use rolling 12-month rates or multi-site averages to spot real performance trends rather than reacting to month-to-month noise. Also compare like-for-like: use the same definitions and time windows when benchmarking against other sites or published industry averages.

Common pitfalls and how to avoid them

• Underreported hours: failing to include all supervised or temporary worker hours will inflate your rate.
• Misclassification: treating recordable medical treatment as first aid (or vice versa) leads to inconsistent year-over-year figures.
• Small sample effects: with low total hours, a single incident can dramatically change your rate. Consider reporting both the raw counts and the normalized rate so readers understand the underlying exposure.
• Inconsistent time windows: don’t compare a single month to a 12-month average unless you convert the base (use 16,667 hours for monthly normalization).

FAQs

Q1. Why is the base 200,000 and can I use something else?

A: 200,000 is the OSHA convention for annualizing rates for a 100-employee workforce; using the same base keeps your results comparable with industry data and regulatory references. For months, use 16,667.

Q2. Should I include contractors and temps?

A: Include hours and incidents for workers your company supervises on a day-to-day basis. If a contractor manages their own workforce and supervision, they may report separately. Confirm supervisory responsibility before deciding.

Q3. One incident inflated our TRIR, is that meaningful?

A: For small hour totals, rates are sensitive. Report raw counts alongside normalized rates, and use rolling averages (e.g., 12 months) to show sustained performance.

Example:
If you had 5 OSHA-recordable incidents and your workforce logged 500,000 hours in the measurement period: TCIR = (5 × 200,000) ÷ 500,000 = 2.00. Use the same formula for DART, LTIR, and Severity (substitute the appropriate case or days value).

Sources: Creative Safety Supply, afety Management Group , Ecesis, MSC Industrial Supply.