The lost-time injury frequency rate

The lost-time injury frequency rate (LTI-rate) is the most commonly used indicator of SHE performance. 

The LTI-rate is defined as the number of lost-time injuries per one million hours of work. A lost-time injury is an injury due to an accident at work, where the injured person does not return to work on the next shift. 

In applications of the LTI-rate in SHE management, we calculate the LTI-rate from statistics on accidents and working hours and compare the results with the pre-established safety goals. We are also concerned with the development of the LTI-rate over time. We will here look more closely into the principles of analysing time series of the LTI-rate before we discuss the merits and shortcomings of the LTI-rate in general. 

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Lost time accidents the lost time injuries frequency rate for employees in 1999 was unchanged from 1998, at 4 per million hours worked. The target figure is 3. The equivalent rate for contractors was 5.5. 

The lost time injury frequency rate (LTIFR) is the most commonly used indicator of HSE performance, and it is defined as the number of lost time injuries per one million hours of work. A lost time injury is an injury due to an accident at work, where the injured person does not return to work on the next shift. However, LTIFR has some deficiencies as a safety performance indicator. It is insensitive to the severity of the injuries, it is possible to manipulate the registration and classification of injuries, use of alternative job (i.e. restricted work), and for small companies LTIFR is fluctuating and sensitive to changes (Kjellen 2000). 

This case provides relatively little support for Worksafe s claims. There was a dramatic drop in the total number of injuries and total injury costs, but this was largely a consequence of the big cut in the workforce. Most of the safety data presented in the study do not take account of this reduction in employee numbers and so are essentially uninterpretable. The one exception is the lost-time injury frequency rate which does show a decline. The new technology played a part in this decline since it is inherently safer than the old. Presumably, attention to OHS also played a part. Finally, it must be stressed that the very substantial increase in productivity which the mill has experienced has nothing to do with improved safety and everything to do with the state-of-the-art technology installed. Any suggestion that the productivity gains at the plant were due to a focus on health and safety would be entirely fallacious. 

Some of the data which apparently support the productivity claim relate to NSW coal mines over the decade of the 1980s and into the 1990s. Figure 10.1, which presents the data relied on by Mathews (1993, p. 48), shows that during the period 1982-1989 the lost-time injury frequency rate, i.e. the number of lost-time injuries per million hours worked, went steadily down while productivity went steadily upwards. 

Figure 3.3 Developments of the lost-time injury frequency rate at an aluminium plant after the introduction of a formal SHE management system. The lost-time injury frequency rate (LTI-rate) is defined as the number of injuries resulting in absence from work per one million hours of work.

Figure 16.1 presents an overview of different SHE performance indicators. This overview is based on the framework for accident analysis in Chapter 6. Loss-based SHE performance indicators will be our starting point. Among these we find the most commonly used indicator, the lost-time injury frequency rate. We proceed by reviewing process-based indicators, similar to those developed in the fertiliser-plant case in Chapter 4. Finally, we will look into indicators relating to causal factors, i.e. indicators based on information about the organisation and SHE management system. 

Figure 17.1 Control chart showing the development of the lost-time injury frequency rate for a steel mill for ten consecutive periods. UCL=Upper Control Limit LCL=Lower Control Limit.

Figures 10.2 and 10.3 show that from 1972 to 1992 the L i tFR (lost-time injury frequency rate) and productivity (measured in terms of output of saleable tonnes of coal per employee per year) followed unrelated trajectories.

The preceding analysis raises the question of just how safety performance is to be measured. Lost-time injury frequency rates are entirely unsatisfactory for at least three reasons. First, as has already... 

Injury experience from workplace accidents can be foimd in mar official pirblica-tions. For a fuller pictirre, the average lost time injury frequency rate and the drrration rate for the injttries need to be cortsidered. You can usually obtain more information from yotu occupational health and safety authority. 

The lost-time injury frequency (LTIFR) rate is calculated using ... 

Lost time accidents in 1998 there were 542 injuries resulting in the loss of one day or one shift of work. The frequency rate has fallen from 1.55 lost time injuries per 100 employees in 1994 to 0.8 in 1998. These figures are against the group target of a frequency rate of less than 1 by 2000. In 1998 only the coatings business had not achieved this target. 

Lost time accidents a graph is given which shows that the injury frequency rate in the USA fell from approximately 3 injuries per 200 000 exposure hours in 1993 to under 2 injuries per 200 000 exposure hours in 1998. 

The recordable injury frequency rate for employees fell from 2.65 injuries per 200 000 hours in 1996 to 1.01 injuries per 200 000 hours in 1999. The figures include both injuries requiring medical attention or that result in restricted work, as well as lost time incidents. 

The LTI frequency rate is not a reliable indicator of the level of safety at Eastern, in part because of the extent to which it is influenced by claims management procedures which result in the conversion of LTIs into injuries without lost time. A further defect is that it fails to highlight major safety failures which need to be taken seriously, regardless of how many lost-time injuries may be occurring. For instance, fatalities are relatively rare, and most mines go for years without a death. However, when they occur they are usually indicative of serious safety deficiencies. Moreover, there are certain kinds of dangerous occurrences with the potential to lead to death or injury which must be reported to the inspectorate, regardless of whether injury has in fact occurred. Every such dangerous occurrence raises questions about standards of safety. 

To improve the follow-up of the risk of injury to personnel, the TRI-rate is introduced. The frequencies of lost-time injuries, restricted-work injuries and medical-treatment injuries are registered separately and in summary and displayed as shown in Figure 17.6. During the first year, the TRI-rate is 30, which makes it a new starting point for improvements. 

It is the responsibility of Norskoil s SHE manager to follow up on the accident statistics from the yards. He monitors the SHE performance in this way and compares the results with the project s goals. NORSOK S-CR-002 defines the requirements as to reporting of accident statistics from the EPC contractor to Norskoil. Based on this information, Norskoil follows up on the following SHE performance measures LTI-rate, LTI -rate (i.e. the frequency of lost-time injuries with potential for severe harm, see Table 17.2) and the TRI-rate. 

Lost time accidents Ashland has a corporate goal to eliminate occupational injuries and illness. For APAC the target date is 2003. In 1999 Ashland s group OSHA recordable frequency rate was 4.87. The rates in the divisions were ... 

Lost time accidents a chart is given showing global frequency rates for OSHA recordable injuries. At DuPont the figure has varied between approximately 0.5 and 1.0 injury per 200000 hours. In 1998 and 1999 the figure was nearer 1.0. 

Lost time accidents the internet report indicates that the global recordable injury/illness frequency rate fell from 5 per 100 employees in 1992 to just over 3 in 1997. The figures in the CER for 1998 and 1999 were 4.63 and 4.93, respectively. 

Lost time accidents NOSA 5 star rating requires a Disabling Incident Frequency Rate (DIFR) of less than one. Most of the South African sites have this rating, and numbers of disabling injuries and incidence rates are given for most sites. 

Indemnity Case Rate, which is a negative metric providing the rate of all workers compensation cases that involve lost time payments per 100 full time employees per year. It may be indicative of the company s basic prevention and reduction efforts in minimizing more serious lost time case incidence and severity. It relates closely to OSHA s DART or rate of injuries and illnesses resulting in days away from work, restricted work activity, and/or job transfer. According to Italian National Standards UNI 7249 (UNI 2007) further index rates are introduced, like incidence index of occurred accidents, defined as rate of occurred accidents per 1.000 workers, frequency index (rate of occurred accidents per 1.000.000 hours worked), severity index of accidents, which represents 1000 times total number of lost days per hours worked. 

The most common unit of workplace injiuy performance is the Frequency Rate. Other rates in common use are the Average Time Lost Rate (Duration Rate) and the Incidence Rate. Some organizations use other rates and indicators to measure their injury experience examples being the Severity Rate and the Frequency-Severity Index. Severity Rate is based on those injuries which lead to more than a defined minimum of lost time. 

Not only do base rate numbers change from country to country, but definitions of the types of accidents may also vary from country to country. It is important to know what definitions are being used for such things as lost time, recordables, first aid cases, and others if you are planning to compare accident frequency rates. For example, the definition of a recordable injury and illness in the United States may be different from the definition used in Canada, Latin America, Asia, or the United Kingdom. In areas where no clearly defined definitions exist, the site must develop its own. This is usually what has to take place in cases of property damage and process interruptions. 

This is a very basic method for calculating upper and lower control limits. Other methods can also be used to calculate these hmits. To ensure that the statistical control charts are as reliable as practical, keep several guidelines in mind. First, use accident rates that have as many sets of data as possible. For example, an aU injury/iUness frequency rate works better than a lost time frequency rate. Second, try to use at least twenty sets of data in calculating the base rate or average. In our example we only used five data points for practical purposes. However, they represented 60 individual monthly frequency rates. 

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