COSS Incident Rate Calculations 2 — Questions and Answers
Question 1: A company with 500 employees working 40 hours/week for 50 weeks had 10 recordable injuries. What is the TCIR?
- 2.0
- 4.0 (Correct answer)
- 1.0
- 5.0
Correct answer: 4.0
TCIR = (10 × 200,000) / (500 × 40 × 50) = 2,000,000 / 1,000,000 = 2.0; wait — hours = 1,000,000, so TCIR = (10 × 200,000) / 1,000,000 = 2.0.
Question 2: Which metric specifically measures the number of days away from work per 100 full-time workers?
- TCIR
- DART rate
- DAFW rate (Correct answer)
- Severity rate
Correct answer: DAFW rate
The Days Away From Work (DAFW) rate counts only cases involving days away, while DART includes both days away and job transfer/restriction cases.
Question 3: A facility's DART rate is 3.5 and its TCIR is 5.0. What percentage of recordable injuries resulted in days away, restriction, or transfer?
- 30%
- 70% (Correct answer)
- 143%
- 50%
Correct answer: 70%
DART/TCIR × 100 = 3.5/5.0 × 100 = 70%, meaning 70% of recordables were serious enough to affect work capacity.
Question 4: In OSHA recordkeeping, 200,000 base hours represents the equivalent of how many full-time workers for one year?
- 50 workers
- 100 workers (Correct answer)
- 200 workers
- 500 workers
Correct answer: 100 workers
200,000 hours = 100 workers × 2,000 hours/year (50 weeks × 40 hours), which is OSHA's standard base for incident rates.
Question 5: An employer recorded 3 injuries: one with 10 days away, one with 5 days of job transfer, and one with no days lost. What is used to calculate the DART rate?
- Only the first injury
- Only the first two injuries (Correct answer)
- All three injuries
- Only the third injury
Correct answer: Only the first two injuries
DART counts cases involving days away from work AND cases of job transfer or restriction, so the first two qualify; the no-days-lost case is counted in TCIR but not DART.
Question 6: A construction site logged 800,000 labor hours and had 6 lost-time injuries. What is the Lost Time Incident Rate (LTIR)?
- 0.75
- 1.50 (Correct answer)
- 3.00
- 0.38
Correct answer: 1.50
LTIR = (6 × 200,000) / 800,000 = 1,200,000 / 800,000 = 1.50.
Question 7: When calculating incident rates, overtime hours worked by employees should be:
- Excluded because they are not standard hours
- Included in total hours worked (Correct answer)
- Counted at 1.5× their actual value
- Capped at 8 hours per shift
Correct answer: Included in total hours worked
OSHA requires all actual hours worked — including overtime — to be included in the denominator when calculating incident rates.
COSS Incident Rate Calculations 2
A company with 500 employees working 40 hours/week for 50 weeks had 10 recordable injuries.
What is the TCIR?