Safety performance is one of the most scrutinized aspects of construction operations, making a clear understanding of key safety metrics critical for executives and safety professionals alike.

Two commonly cited metrics are the Lost Time Incident Rate (LTIR) and the Total Recordable Incident Rate (TRIR). Both are standard OSHA-derived indicators that measure workplace injuries in terms of frequency, but they focus on different types of incidents.

LTIR zeroes in on more severe injuries that result in lost work days, while TRIR captures all OSHA-recordable injuries, from minor to severe.

In this guide, we break down LTIR and TRIR in practical terms, including:

• What each metric measures and how it is calculated (formulas and examples)
• Key differences in their scope and what they indicate about safety performance
• Typical benchmarks in construction (how to interpret your rates relative to your trade, risk profile, and multi-year trends)
• Why these metrics matter for construction companies (impact on compliance, reputation, and operations)
• Limitations of relying on LTIR and TRIR alone, and how to use them as part of a broader safety strategy

Our goal is to equip construction executives, project leaders, and safety managers with a clear understanding of these metrics – enabling their teams to interpret the numbers correctly and strengthen their safety programs accordingly.

What is Lost Time Incident Rate (LTIR)?

Lost Time Incident Rate (LTIR) – sometimes called the Lost Time Injury Rate or Lost Time Injury Frequency Rate (LTIFR) – is a safety metric that measures how often work-related injuries or illnesses cause an employee to miss work, standardized per a set number of hours worked. In other words, LTIR answers: “How frequently do injuries occur that are serious enough to result in one or more days away from work?”

To count as a “lost time” incident (LTI), an injury must be severe enough that the worker cannot return to their next scheduled shift or subsequent shifts. For example, if a construction worker fractures their arm and must remain home or in recovery for one or more workdays, that incident is a lost time case and contributes to the LTIR.

By contrast, if a worker suffers a minor laceration that requires stitches (making it OSHA-recordable) but can come back to full duty the next day, the incident would not count towards their LTIR because no time away from work occurred, even though it would count toward their TRIR.

LTIR, therefore, focuses on the more severe subset of injuries that directly impact labor hours and productivity by causing absences.

How is LTIR Calculated?

LTIR is calculated with a formula very similar to other OSHA incidence rates (like TRIR), normalizing the number of cases to a standard labor exposure of 200,000 hours. The formula is:

LTIR = (Number of lost time cases × 200,000) / (Total hours worked by all employees in the period)

The constant 200,000 in the formula represents the base hours worked by 100 full-time employees in one year (100 workers × 40 hours/week × 50 weeks). Using this standard base allows companies of different sizes to be compared on an equal scale (per 100 full-time workers ). The result of the calculation represents the number of lost-time incidents per 100 full-time workers, based on actual hours and recorded cases.

For example, suppose a construction firm had 2 incidents in a year where employees missed days of work (lost time injuries), and the total hours worked by the company that year were 400,000. The LTIR would be:

LTIR = (2 × 200,000) / 400,000 = 1.0

In this case, the company’s LTIR is 1.0, meaning the equivalent of 1 lost-time injury per 100 workers in a year. A higher LTIR indicates that serious, work-disrupting injuries are occurring more frequently. A lower LTIR means such severe incidents are rarer – ideally, companies aim for an LTIR of 0.0, indicating no injuries that resulted in missed work.

What LTIR Indicates in Safety Performance

LTIR reflects the rate of significant injuries – those that impact workers’ ability to do their jobs. A low LTIR indicates fewer cases resulted in days away from work — and can be a positive signal when evaluated alongside factors such as work type, exposure controls, and multi-year trends. Conversely, a high LTIR is a red flag that employees are regularly getting hurt badly enough to miss work, pointing to potential deficiencies in safety controls.

It’s important to note that LTIR excludes less severe injuries only involving medical treatment or restricted duty, but no days away from work. As a result, the more minor and moderate injuries are not captured. For instance, if a company had numerous recordable cases where workers returned immediately on light duty, those wouldn’t raise the LTIR. This means LTIR by itself provides insight into how often injuries with more severe outcomes happen, but not the full picture of all injuries.

In practice, companies look at LTIR alongside TRIR (and related metrics like DART) to balance frequency and severity. By tracking LTIR trends over time, organizations can see if their serious-injury rate is improving or worsening, and target interventions to prevent more high-consequence events (falls, major traumas, etc.).

Finally, LTIR tends to be lower in value than TRIR, since it’s a subset of incidents. LTIR will always be less than or equal to the TRIR, because every lost-time case is recordable, but not every recordable is lost time. This relationship and other differences will be explored further below.

What is Total Recordable Incident Rate (TRIR)?

The Total Recordable Incident Rate (TRIR) – also known as the Total Recordable Injury Rate or Total Case Incident Rate (TCIR) – is a standard OSHA metric that measures the overall frequency of all OSHA-recordable injuries and illnesses that occur in a workplace, normalized per 100 full-time workers. In simple terms, TRIR answers: “How many OSHA-recordable incidents did we have, relative to hours worked?”

Under OSHA recordkeeping rules (29 CFR 1904), a case is “recordable” if it is work-related and involves medical treatment beyond first aid, or results in death, days away from work, restricted work or job transfer, or loss of consciousness. This definition casts a wide net: it includes everything from a serious accident that causes weeks off work to a moderate injury like a deep cut requiring stitches (even if the worker missed no days). First-aid-only incidents are not recordable. Essentially, if an injury or illness is significant enough to require professional medical intervention (stitches, a fracture, prescription medication, etc.) or any time off or work restrictions, it counts toward TRIR. TRIR, therefore, is a comprehensive frequency metric for workplace injuries/illnesses, regardless of severity, as long as they meet the OSHA criteria for recordability.

How is TRIR Calculated?

TRIR is calculated using a very straightforward formula set by OSHA and the Bureau of Labor Statistics. The formula is:

TRIR = (Number of OSHA-recordable cases × 200,000) / (Total hours worked by all employees in the period)

This is the same basic form as the LTIR formula – and indeed, both metrics are incidence rates per 200,000 hours. The 200,000 figure serves the same purpose here: to normalize incident frequency to a standard number of workers for fair comparison. A TRIR of 2.0, for example, means 2 recordable injuries per 100 workers over the period in question.

For example, if a contractor had 5 recordable injuries last year and employees worked 250,000 hours in that year, the TRIR would be:

TRIR = (5 × 200,000) / 250,000 = 4.0

This result (4.0) would indicate that the company experienced the equivalent of 4 recordable cases per 100 workers. In practical terms, it means injuries occurred fairly frequently – a TRIR of 4.0 is higher than the construction industry average and could potentially be cause for concern (more on benchmarks in a moment).

Because the calculation is simple and based on OSHA logs (Form 300/300a data), TRIR is easy for any organization to compute and report. It’s a universally understood metric in safety: executives and safety professionals often ask “What’s our TRIR?” as a quick gauge of safety performance. Regulators (OSHA, BLS) and industry groups also publish average TRIR values for various industries each year, which companies use to benchmark themselves.

What TRIR Indicates in Safety Performance

TRIR is a frequency indicator – it tells you how often recordable injuries are happening, but not how severe they are. Every recordable case carries equal weight in TRIR. This means a minor injury (say, a cut requiring a few stitches) and a major injury (like an amputation) each add “1” to the count. A lower TRIR indicates fewer injuries relative to hours worked, which generally reflects stronger safety performance and hazard control, since incidents are rarer. A higher TRIR means injuries are occurring more frequently, signaling poorer safety outcomes or higher risk exposure.

However, TRIR alone does not distinguish severity. A company could have a low TRIR one year, but that could include a single catastrophic injury; meanwhile, another company might have a higher TRIR composed of only small incidents. For this reason, TRIR is often paired with metrics like DART or LTIR to give more context. TRIR also excludes near-misses and first aid cases, so it doesn’t capture close calls or minor incidents that may serve as warning signs for potential future incidents. Safety professionals interpret TRIR trends over multiple years to see if overall injury frequency is rising or falling, but they are careful not to treat it as the sole indicator of safety performance.

Another aspect to consider is company size and statistical fluctuation. Especially for small firms or short time frames, TRIR can be volatile – one or two incidents can swing the rate drastically. Research has shown that for many companies, recordable incidents occur somewhat randomly and that a single year of TRIR data is not a reliable predictor of future risk. In fact, an extensive analysis in 2021 found no consistent association between a contractor’s one-year TRIR and its likelihood of a future fatality, concluding that differences in TRIR, especially among small samples, are often due to chance rather than true safety performance. OSHA acknowledges this issue, too, recommending that small employers look at multi-year averages to get a more meaningful trend. The takeaway is that TRIR is best used as a broad lagging indicator of past injury frequency – useful for big-picture benchmarking and spotting long-term trends, but not a precise yardstick of safety culture or a crystal ball for future incidents.

It is important for organizations to recognize that both TRIR and LTIR alone do not provide sufficient context to improve safety performance. To make meaningful improvements, companies must examine the incidents making up both their TRIR and LTIR and understand patterns, including:

• Where incidents are occurring
• Which activities most frequently lead to incidents
• Which trades and job titles are most often involved
• The most common causes of incidents
• The body parts most frequently injured
• The tools or equipment most often in use at the time of injury

Understanding this additional context is what empowers organizations to truly understand their TRIR and LTIR and make impactful changes. A detailed view of these factors helps organizations focus training, inspection, and planning efforts on the conditions and activities that are contributing to recordable and lost-time incidents.

LTIR vs TRIR: Key Differences

While both LTIR and TRIR are calculated in the same way (incidents per 200,000 hours) and both are based on OSHA recordkeeping data, they measure different slices of safety performance. Here are the key differences and what they mean in practice:

• Scope of Incidents: TRIR counts all OSHA-recordable incidents, encompassing everything beyond first aid – from minor injuries up through the most serious cases. LTIR counts only a subset of those incidents: the ones serious enough to cause lost workdays. In other words, every lost-time injury is by definition a recordable incident (and will factor into TRIR), but not every recordable incident will count toward LTIR. For example, an injury resulting in just restricted duty or medical treatment contributes to TRIR but not to LTIR, since the worker didn’t miss time. LTIR thus filters the recordable cases down to those with the most significant impact on the worker.
• Frequency vs. Severity Focus: Because of that scope difference, TRIR is a broader frequency metric – it tells you how often workers are injured overall. LTIR is a frequency of severe injuries – it tells you how often workers are getting hurt badly enough to miss work. In practical terms, TRIR can be seen as an overall injury rate, whereas LTIR is a critical injury rate, as lost-time cases often correspond to higher-severity incidents. If TRIR is high but LTIR remains low, it suggests many incidents are occurring, but they tend to be minor (no days lost). If LTIR is high, it indicates a problem with more serious accidents. By comparing the two, safety professionals gain insight into not just how many people are getting hurt, but also whether those injuries are resulting in severe outcomes like time away from work.
• Numerical Relationship: Since LTIR is a subset of recordables, LTIR will always be less than or equal to TRIR. If a company has no lost time cases in a year, its LTIR would be 0.0 even if it had recordable injuries. If every recordable incident involved days away, then LTIR and TRIR would be the same value (because every case counted in TRIR also counted in LTIR). Typically, you’ll see TRIR > LTIR, and the gap between them reflects how many recordable injuries did not result in lost time. For instance, a TRIR of 4.0 vs an LTIR of 1.0 in the same year tells us that many injuries did not result in time away from work. A small gap (say TRIR 2.0 vs LTIR 1.5) would imply that most recordables were quite severe (nearly all involved lost days).
• Use Cases and Emphasis: TRIR is widely used as a headline safety metric for companies and projects–but it’s best treated as a broad benchmarking input, not a standalone indicator of risk. LTIR is often used internally to monitor and manage serious injuries, and is of interest to stakeholders concerned with the impact of injuries on operations (e.g., project managers and insurers focus on lost-time cases). Many firms track LTIR alongside TRIR to ensure they receive insight on both overall injury frequency and the frequency of more severe injuries. For example, management might set goals to reduce TRIR year-over-year, but also pay close attention to LTIR to ensure they’re reduced life-altering or costly injuries that hit productivity hardest.

In summary, TRIR captures the total frequency of injuries, whereas LTIR drills down to the frequency of the most significant injuries (those causing lost work time). Both are lagging indicators of past incidents; together, they provide a more complete picture: TRIR shows how often workers are getting hurt in general, and LTIR shows how often they’re getting hurt badly enough to miss work.

Example Scenario: Comparing LTIR and TRIR

To illustrate the difference between these metrics, let’s consider a realistic scenario. Imagine a mid-sized construction contractor with about 100 full-time employees (≈200,000 work hours per year). In the past year, the company experienced 5 OSHA-recordable incidents in total. Here’s the breakdown of those 5 cases:

• 1 incident was very serious and resulted in a worker being off work for several weeks
• 1 incident resulted in the worker being on restricted light duty for a few days, but no days away (this is a DART case but not a lost-time case, since the employee didn’t miss an entire shift).
• The other 3 incidents were recordable because they required medical treatment beyond first aid (e.g., stitches, a minor fracture, etc.), but the workers returned to full duties the next day with no lost time or restrictions.

Now, let’s calculate the rates for this scenario:

• TRIR: There were 5 recordable cases total. Using the formula, TRIR = (5 × 200,000) / 200,000 = 5.0. So the company’s TRIR is 5.0, meaning the equivalent of 5 recordable injuries per 100 workers in a year. This TRIR of 5.0 counts all the incidents, from the one major case to the few minor ones.
• LTIR: Out of those 5 recordables, only 1 case actually led to days away from work. So, LTIR = (1 × 200,000) / 200,000 = 1.0. The company’s LTIR is 1.0, meaning 1 lost-time injury per 100 workers. This reflects only the severe injury that resulted in missed work.

In this scenario, the TRIR (5.0) is much higher than the LTIR (1.0). That gap tells us that many of the recordable injuries did not cause lost workdays. The TRIR of 5.0 indicates a relatively high overall injury frequency (5 cases in one year for this workforce size, which is above industry norms). Meanwhile, an LTIR of 1.0 indicates that only one of those incidents had a serious outcome (lost time).

This example is typical of what you might see: the LTIR is a subset of the TRIR. Stakeholders may look at this and conclude that, although the company had numerous injuries, most were minor in nature. They would likely investigate why the recordables occurred (to reduce the TRIR) and examine the circumstances of the lost-time injury to prevent such serious incidents in the future. If, hypothetically, all 5 recordable injuries had resulted in days away from work, then both TRIR and LTIR would be 5.0. In many real cases, though, TRIR will be higher than LTIR, and the difference between the two numbers indicates how many incidents were relatively minor versus serious.

To put it another way: TRIR answers “How many people got hurt?” while LTIR answers “How many people got hurt badly enough that they couldn’t work?” Looking at both together gives a nuanced view: you want both numbers as low as possible, but a gap between them suggests that some injuries, though frequent, are not devastating – which might influence where you focus safety efforts.

Why LTIR and TRIR Matter in Construction

Maintaining low LTIR and TRIR rates isn’t just about bragging rights or statistics – these metrics have real consequences for compliance, competitiveness, and the bottom line in the construction industry. Here are a few reasons why they matter:

Benchmarking and Reputation

TRIR and LTIR allow construction companies to benchmark their safety performance against industry averages and peers. Each year, the U.S. Bureau of Labor Statistics (BLS) publishes average incident rates for various industries. For example, recent BLS data shows that the construction industry’s average TRIR was about 2.3 in 2023, with an average lost-time case rate around 1.0.

Companies that consistently perform better than these benchmarks (i.e., have lower rates) can highlight that achievement in bids and marketing, enhancing their reputation as a safe contractor. A firm with a TRIR or LTIR well below industry average is often perceived as a lower-risk choice–though owners still need to validate exposure controls, work scope, and severity risk.

On the flip side, a contractor with rates significantly worse than average will attract negative scrutiny. Clients and partners often take these numbers into account during their prequalification processes. Internally, tracking these metrics year-over-year fosters a culture of continuous improvement.

Project Prequalification and Contracts

It’s common in construction for project owners or general contractors to ask for a company’s TRIR (often a 3-year average) and related metrics during prequalification or bidding. Many large construction clients have thresholds they want their contractors to meet. For instance, they may be wary of hiring a subcontractor with a TRIR above a certain number (often the industry average or a fixed cutoff like 3.0). If a contractor’s rates are higher than their thresholds, they may be disqualified from bidding or required to go through a more in-depth risk mitigation process.

In short, a low TRIR/LTIR can open doors to more projects, whereas high rates can make it harder to win work. As an example, if a subcontractor reports a TRIR of 5.0 when peers average ~2.5, they may be asked to provide detailed explanations for their rates and complete corrective-action plans to even be considered for certain projects. Thus, keeping these metrics in check directly affects a company’s ability to win work.

Insurance and Financial Impact

Safety performance metrics have a well-established link to insurance costs in construction. A history of frequent injuries (high TRIR) or serious injuries (high LTIR) increases workers’ compensation claims, which in turn can increase the company’s Experience Modification Rate (EMR) and insurance premiums. Insurers view high incident rates as a sign of greater risk, and they will charge more to cover that risk. Particularly, lost-time injuries tend to be the most costly type of claims (medical bills plus wage indemnity for missed work), so a high LTIR often signals expensive claims that will hit your EMR. Conversely, a low TRIR and LTIR over multiple years can help keep your EMR low (below 1.0), yielding insurance premium discounts.

In addition, every injury has direct and indirect costs: medical treatment, lost productivity, project delays, hiring/training replacement workers, potential OSHA fines, etc. The costs of these incidents across the industry are massive. The average construction claim is estimated to be over $41,000, while more severe incidents can cost over $100,000 each. It is also estimated that for every $1 in direct workers’ compensation costs, about $2.12 in indirect costs are incurred. Total workers' compensation costs across the construction industry are estimated at over $12 billion annually. By preventing incidents – i.e., keeping TRIR and LTIR down – companies avoid these costs and improve profitability. In summary, safety metrics are directly tied to financial performance: they affect insurance rates and the costs of accidents.

Operational Continuity and Morale

In construction, when a worker is injured, especially with a lost-time injury, it doesn’t just affect that individual – it affects the whole project. A high LTIR means frequent disruptions: key crew members missing work or working at reduced capacity. This can slow down schedules, force reallocating tasks, or require bringing in temporary labor. Tracking LTIR helps management see how often such productivity hits are happening. A low LTIR, by contrast, means you rarely have those disruptions, which contributes to smoother project delivery.

A high LTIR can point to opportunities for improvement, such as strengthening return-to-work practices. A well-designed return-to-work program helps identify appropriate modified or restricted duty options, enabling injured employees to return safely and productively sooner. This approach can reduce lost workdays, support recovery, and help limit the overall cost and operational impact of injury claims.

A high TRIR can indicate broader safety issues that can also impact worker morale and efficiency. Workers who see colleagues getting hurt frequently may feel the site is unsafe, potentially leading to lower morale or even work slowdowns. A strong safety record (low TRIR and LTIR) contributes to an environment where workers can focus on their jobs without fear, and where teams spend less time responding to incidents. In essence, good safety metrics align with good operational performance: fewer accidents equal less downtime and a more confident, productive workforce.

In summary, clients, insurers, and employees are all paying attention to or are impacted by these metrics. The goal isn’t to optimize a rate — it’s to reduce real risk: preventing serious incidents, protecting workers, and keeping projects on track. In other words, it’s about people not getting hurt, projects staying on track, and being seen as a trusted, reliable contractor. Many leading construction firms now set corporate targets for these metrics (e.g., “TRIR below 1.5” or “Zero Lost Time Incidents annually”) and tie management performance goals or incentives to them, underscoring how integral they are to business success.

Limitations of Relying on LTIR and TRIR

Despite their importance, LTIR and TRIR (like any lagging indicators) have limitations that safety professionals should keep in mind. Overreliance on these rates can be misleading or even encourage behaviors like intentional underreporting. Here are some key limitations:

Lagging Indicators – Reactive, Not Predictive

TRIR and LTIR are lagging metrics that reflect what injuries occurred, not the hazards, near-misses, or prevention efforts that preceded them. They also provide no insight into how companies responded to these injuries and how they are preventing future incidents. That’s why these metrics should be balanced with leading indicators that provide insight on how risks are being controlled, rather than solely focusing on injury outcomes.

No Severity Granularity (Especially TRIR)

TRIR counts all OSHA-recordable cases equally, offering no distinction between minor recordables and life-altering events. LTIR narrows the focus to more serious injuries but remains binary, failing to capture how severe the injury was or how much time was actually lost. It is important for organizations to understand how severe their lost-time injuries are, an insight that LTIR alone does not provide. To truly understand impact, safety teams must review underlying details–such as comparing total lost workdays to days away cases, revealing how many days away are being experienced per lost time case.

Statistical Variability and Small Numbers

For small contractors or crews, a single incident can dramatically inflate TRIR or LTIR due to low total hours worked. These swings often reflect statistical noise rather than real changes in safety performance, especially when viewed year to year. Industry experts recommend evaluating multi-year trends or rolling averages to avoid drawing conclusions from short-term fluctuations.

Under-Reporting and Data Integrity Issues

TRIR and LTIR rely on accurate reporting, which can be affected when organizations feel pressure to keep rates low. Injuries may be under-reported or reclassified to avoid lost-time designations, artificially deflating results, while overly cautious reporting can inflate them. Strong safety cultures emphasize honest, blame-free reporting, so these metrics reflect reality.

Context Is Critical

A TRIR or LTIR loses meaning without also understanding company size, scope of work, and historical trends. One incident can skew results for a small contractor, while a higher rate may be reasonable in a higher-risk niche compared to industry averages. These metrics should be used as conversation starters–paired with context and narrative–not as standalone judgments of safety performance.

How Highwire Uses TRIR and Lost-Time Metrics

Highwire uses TRIR, LTIR, and other incidence rates as benchmarking inputs—then places them in a broader, risk-based evaluation designed to avoid decision-making based only on these rates. Contractors submit three years of OSHA 300a data so Highwire can calculate multi-year averages that reflect both overall and severe incident frequency.

Benchmarking Against Industry Risk

Highwire benchmarks each contractor’s three-year average TRIR and LTIR rates against the latest BLS industry averages for their specific trade. This ensures contractors are evaluated relative to the inherent risk of their work, not against a one-size-fits-all standard. A rate that is acceptable in one trade may be elevated in another, and Highwire’s model accounts for those differences.

Impact on Highwire’s Safety Score

TRIR is a key input within Highwire’s 0–100 Safety Score, and lagging indicators like incident rates and claims history influence the score alongside leading indicators. Contractors with rates well below industry averages earn higher scores, while those with abnormally high rates are flagged for further review. This approach ensures incident history meaningfully influences risk assessment without being the sole determinant.

Trend Visibility and Decision Support

Highwire’s dashboards allow users to visualize TRIR and LTIR trends over time alongside industry benchmarks. Trend analysis highlights whether a contractor’s performance is improving, stable, or showing concerning spikes that may warrant follow-up. This helps owners and safety teams quickly identify patterns rather than relying on single-year snapshots.

A Balanced, Holistic Evaluation

Importantly, Highwire treats TRIR and lost-time rates as inputs–not final verdicts–on contractor safety performance. The platform balances these lagging indicators with evaluations of safety programs, training, certifications, and other leading indicators. This holistic approach ensures contractors are assessed based on both their incident history and the systems they have in place to prevent future incidents, helping clients focus on real risk rather than just chasing low numbers.

Categorizing Incidents as SIF-p

Highwire offers a tool that allows for incidents to be classified as SIF-p, identifying cases that had the potential to result in a serious injury or fatality. Understanding what percentage of recordable and lost-time cases fall in this category helps organizations focus prevention efforts on the exposures and conditions most likely to result in the most serious outcomes, rather than treating all incidents as equal in risk.