Incident rates such as LTIR indicate not just the number of incidents that have occurred but also how severe they were. As measurements of past performance or lagging indicators, they are very useful in assessing your current safety system. Besides, LTIR is one of the metrics that must be reported to the Occupational Safety and Health Administration (OSHA), so an LTIR calculation is a major to-do on any Safety Manager’s list in the United States.
Contents hideBefore we begin, let’s clear some of the clouds when it comes to recordkeeping and lost time incidents. Here are the most commonly used terms and their meaning.
| LTI: Lost Time Incident | Individual occurrences of injury in the workplace which results in the employee having to take a minimum of one full working day away from work. |
| LTIR: Lost Time Incident Rate | A metric used to determine the rate of LTIs per 100 employees sometimes referred to as lost time injury rate. |
| TRIR/TCIR: Total Recordable Incident Rate/ Total Case Incident Rate | The total number of incidents resulting in employee injuries, whether leading to time away from work or not. |
| LTC Rate: Lost Time Case Rate | Represents solely the number of cases that resulted in lost work days. This isn’t a standard OSHA metric but is used by some organizations internally. |
Before going into what LTIR is, let’s clarify what lost time is. First, there is no such term as “lost time”. The correct OSHA term is “lost workday case”.
“For OSHA injury and illness recordkeeping purposes, the term “lost workday case” is used to designate cases involving days away from work and/or days of restricted work activity beyond the date of injury or onset of illness (page 47, section B). OSHA does not use the term “lost time cases”.”
That being said, OSHA defines lost time (lost workday case) as follows,
“For OSHA injury and illness recordkeeping purposes, the term “lost workday case” is used to designate cases involving days away from work and/or days of restricted work activity beyond the date of injury or onset of illness (page 47, section B).”
And they advise,
“When counting the number of days away from work or days of restricted work activity, do not include: (1) The initial day of injury or onset of illness, or (2) any days on which the employee would not have worked even though able to work (holidays, vacations, etc.).”
Now that we clarified what lost time is (and isn’t), defining LTIR is much easier.
Lost Time Incident Rate (LTIR) is a metric used to record the average number of incidents leading to an employee being unable to work for a minimum of one day during a set period.
You’d use the overall number of lost time incidents (LTI), as defined above, within an LTIR calculation. You can then use the resulting figure to compare the business’ safety performance against the industry and national averages.
Safety leaders must post LTIR to OSHA annually via the 300 and 300a forms. The agency could potentially use it for enforcement action. The good news is this typically happens only when your rates have been consistently high for a number of years.
So, how is this different than TRIR?
All incidents which result in occupational injury will be recorded using Total Case Incident Rate (TCIR) or Total Recordable Incident Rate (TRIR). Only those which result in more than one day away from work (LTIs) are recorded using LTIR.
| LTIR Example An incident in which an employee suffers an occupational injury, but can return to work the following day will be recorded as a part of the TRIR/TCIR calculation but does not need to be included in the LTIR. If he is away for a few work days while recovering, however, this must be recorded in both. |
Not all employers need to keep LTIR records. Companies with 10 or fewer employees are exempt, as are businesses within some industry classifications. Full details of exemptions can be found in the full LTIR OSHA exemption regulation.
The LTIR of a company gives employees, insurers, and stakeholders an indication of how safe the company’s practices are. A high number means that more employees have had to take time away from work due to work-based incidents. This could result in higher insurance premiums and good employees seeking to leave the company over fears for their health and safety.
Conversely, a low LTIR can have a positive impact on insurance rates and shows potential employees and investors that the company has a reputation for safe working practices.
LTIR can be lowered organically by cultivating a safe working environment and engaging employees in safety best practices.
To calculate the LTIR, you will need to know the following:
You can then plug these figures into the following LTIR calculation formula:
([number of lost time injuries in the reporting period] x 200,000)/(total hours worked in the reporting period)
If you don’t want to do this calculation with pen and paper, help yourself to our free LTIR calculator.
