What Is a Lost Time Injury? (Definition)
A Lost Time Injury — commonly abbreviated as LTI — is a work-related injury or illness that results in an employee being unable to work their next scheduled shift or regular duties. It is a serious lagging indicator because it shows that harm has already occurred and productive work time has been lost.
In OSHA recordkeeping, these cases are generally captured as "days away from work" cases when they meet the recordability criteria. Outside the United States, organisations may use similar definitions under local reporting rules, but the core idea is the same: an injury was severe enough to remove a worker from normal work.
What Counts as an LTI?
Common Lost Time Injury examples include:
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A worker suffers a fracture after a fall and cannot return for several days
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A forklift collision causes an injury requiring days away from work
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A hand injury from machinery prevents the employee from performing normal duties
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A back strain from manual handling keeps a worker off their next scheduled shift
How to Calculate LTIFR
LTIFR stands for Lost Time Injury Frequency Rate. It normalises LTIs by hours worked so safety teams can compare sites, contractors, and time periods fairly.
LTIFR = (Lost Time Injuries × 1,000,000) ÷ Hours Worked
Some organisations, especially those aligning with OSHA-style rate calculations, use 200,000 instead of 1,000,000:
LTIR = (Lost Time Injuries × 200,000) ÷ Hours Worked
The 200,000 constant represents 100 full-time workers over a year. The 1,000,000 convention is common in international reporting and expresses LTIs per one million hours worked.
A manufacturing site records 4 lost time injuries across 800,000 hours worked.
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Using the one-million-hour convention: (4 × 1,000,000) ÷ 800,000 = 5.0
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Using the 200,000-hour convention: (4 × 200,000) ÷ 800,000 = 1.0
This means the site has an LTIFR of 5.0 per million hours, or an OSHA-style lost time rate of 1.0 per 100 full-time workers.
LTI vs TRIR vs DART Rate: Key Differences
| Metric | What It Measures | Typical Formula Constant | Safety Meaning |
|---|---|---|---|
| LTI / LTIFR | Injuries causing time away from work | 1,000,000 or 200,000 | Severity-focused lagging indicator |
| TRIR | All OSHA recordable incidents | 200,000 | Broad recordable injury rate |
| DART Rate | Days Away, Restricted, or Transferred cases | 200,000 | Lost work capacity and job limitation |
| Near Miss | Harm nearly occurred, but did not | Not rate-based | Leading indicator for prevention |
Why LTI Matters for Safety Teams
Lost Time Injuries matter because they indicate serious harm, operational disruption, and possible gaps in hazard controls. A rising LTIFR can point to unsafe work design, weak supervision, poor housekeeping, equipment interaction risks, or procedures that do not match real work.
For EHS leaders, LTI performance affects:
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Worker wellbeing and return-to-work outcomes
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Insurance costs, compensation claims, and contractor qualification
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Customer, regulator, and board-level confidence
How AI and Computer Vision Help Reduce Lost Time Injuries
Traditional LTI analysis starts after an injury has already happened. AI-powered safety platforms like Safvr help safety teams act earlier by identifying the unsafe acts, conditions, and near misses that often precede serious injuries.
Safvr uses computer vision, real-time logging, video evidence, trend dashboards, and predictive risk scoring to detect patterns such as unsafe forklift-pedestrian interaction, missing PPE, blocked walkways, line-of-fire exposure, and poor zone compliance before they become lost time injuries.
How Safvr Helps You Reduce LTIs
Safvr helps organisations move from reacting to lost time injuries to preventing the conditions that cause them. Key capabilities include:
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Computer-vision detection of high-risk behaviours and hazardous conditions
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Real-time incident and near miss logging with timestamped video evidence
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Predictive risk scoring to prioritise the areas most likely to produce severe incidents