The Lost Time Case Rate, also referred to as LTC Rate, is a standard workplace safety metric like OSHA’s Total Recordable Incident Rate. Where the TRIR considers all injuries and illnesses, the LTC Rate represents solely the number of cases that resulted in lost workdays. OSHA defines a lost time case as a recordable incident where an employee cannot return to work or is given restricted work.
There can be several different reasons why an employee may have to call out of work. Incidents such as trips, slips, or falls may have caused an employee to break a bone or sprain an ankle. Or perhaps they were exposed to a hazardous chemical that resulted in a level of injury that prohibited a fast recovery. Whatever the type of injury, a high injury frequency rate within business operations must be addressed to further improve the facility’s safety program. Without these improvements, insurance premiums may go up, jobs may not be filled because of a bad reputation, and productivity and product quality can plummet.
To determine your LTC Rate, first plug in number of recordable cases with associated lost workdays – this information can be found in your OSHA 300 or 300A log. While it’s common to input the number of employee labor hours worked over a year, you can choose any given time frame for your calculation. For instance, calculating the LTC Rate monthly will make it easier to spot trends from month to month.
I’ve calculated the Lost Time Incident Rate, what's next?
The rate calculated above is the number of workers who lost time due to an injury or illness for every 100 employees – the more hazardous types of industries such as commercial fishing, logging, or mining are likely to have a higher Lost Time Incident Rate.
EHS managers use the Lost Time Case Rate to monitor the impact of lost time on a business, track the impact of safety measures, and identify trends.
Lowering your Lost Time Case Rate begins with reviewing the following:
- Training: Ensure safety training is proactive and up to date; double check certification requirements and safety program procedures.
- Safety Controls: Complete a risk analysis to gather essential data and then implement preventative measures like machine guards, visual cues, and more to reduce the likeliness of an incident.
- Procedures: Perform preventative maintenance. This can greatly reduce the chance of an injury resulting from dangerous machinery or equipment.
- Past Incidents: Look at past injuries and illnesses to determine the root cause of each incident. Solving each issue can not only reduce duplicate incidents but can also prevent similar problems.
Understanding Key Workplace Safety Metrics
Below is a comprehensive reference table of essential safety metrics that can help your organization track, assess, and improve workplace health and safety performance. From calculating your Accident Frequency Rate (AFR) to using a DART Rate Calculator for determining the Days Away/Restricted or Job Transfer Rate, each metric offers valuable insights. You’ll also find guidance on the Lost Time Injury Frequency Rate (LTIFR), the Lost Time Case Rate (LTIR), and the Lost Workday Rate (LWDR), each of which provides a clearer understanding of how incidents translate into lost work hours. Additionally, tools like a Severity Rate Calculator and methods for determining the Total Case Incident Rate (TCIR), Total Recordable Injury Frequency Rate (TRIFR), and OSHA Recordable Severity Rate (TRSR) ensure you can accurately measure the full impact of workplace incidents. By leveraging these metrics, your organization can identify safety trends, implement preventive measures, and maintain a proactive approach to hazard control.
| Name | Acronym | Definition | Formula |
|---|---|---|---|
| Accident Frequency Rate Calculator | AFR | Number of incidents resulting in lost work time due to injury or illness per 100 employees. | (Number of Accidents × 200,000) / Total Hours Worked |
| Days Away/Restricted or Job Transfer Rate | DART | Number of incidents resulting in lost work time, restricted duties, or job transfers per 100 employees. | (Number of DART Cases × 200,000) / Total Hours Worked |
| Lost Time Injury Frequency Rate | LTIFR | Number of injuries resulting in lost time per 1,000,000 hours worked. | (Number of Lost Time Cases × 1,000,000) / Total Hours Worked |
| Lost Time Case Rate | LTIR | Number of incidents resulting in lost time per 100 full-time employees. | (Number of Lost Time Cases × 200,000) / Total Hours Worked |
| Lost Workday Rate (Lost Time Injury Rate) | LWDR | Number of lost workdays due to injury or illness per 100 full-time employees. | (Number of Lost Workdays × 200,000) / Total Hours Worked |
| Severity Rate | SR | Number of lost days relative to total hours worked per 100 full-time employees. | (Number of Lost Workdays × 200,000) / Total Hours Worked |
| Total Case Incident Rate (OSHA Recordable Incident Rate) | TCIR | Number of OSHA recordable incidents (injuries and illnesses) per 100 full-time employees. | (Number of OSHA Recordable Cases × 200,000) / Total Hours Worked |
| Total Recordable Injury Frequency Rate | TRIFR | Number of fatalities, lost time injuries, restricted duty cases, and other injuries requiring medical treatment per 1,000,000 hours worked. | (Number of Recordable Injuries × 1,000,000) / Total Hours Worked |
| OSHA Recordable Severity Rate | TRSR | The average number of lost and restricted days per OSHA recordable incident. | (Number of Lost Work Days + Number of Restricted or Transferred Days) / Number of OSHA Recordable Incidents |
