Incident-rate measures accidents

In addition, the results tend to establish the applicability of a behaviorally based, positive measure of safety. Such a measure is useful for measuring and enhancing the presence of safety while other, after-the-fact measures based on accident/incidence rates measure only the absence of safety. 

End-of-pipe measures continue to be vitally important. The largest PSM and ESH management costs are accident and incident related. If you reduce the costs of managing PSM and ESH, yet accident and incident rates rise beyond any normal statistical variation, the new system is costing the company more. Near misses are a leading indicator for accidents and incidents and should not be neglected. 

Another way of measuring accident performance is by the LTIR, or lost-time injury rate. This is identical to the OSHA incidence rate based on incidents in which the employee is unable to continue their normal duties. A plant site has 1200 full-time employees working 40 hr/week and 50 weeks/yr. If the plant had 2 lost-time incidents last year, what is the LTIR ... 

Two of the more easily recognized industry measures include the accident rate and the injury incident rate ... 

With these activity-based performance measures, there is also a variety of safety metrics that can be used to assess program performance. As identified by OSHA in studies ofVPP organizations, OSHA injury incidence rates, lost work day rates, and workers compensation losses are a few safety metrics that have been correlated to the performance of the VPP criteria activities. These measures can easily be expanded to include unsafe behaviors, accident trends, and near misses. 

The simplest measure of accident rate is called the incident rate and is defined as ... 

Any simple measurement of performance in terms of accident (injury) frequency rates or accident/incident rate is not seen as a reliable guide to the safety performance of an undertaking. The report finds there is no clear correlation between such measurements and the work conditions, in injury potential, or the severity of injuries that have occurred. A need exists for more accurate measurements so that a better assessment can be made of efforts to control foreseeable losses. 

The OSHA incidence rate is the number of injuries and illnesses per 200,000 hours of e q)Osure. Any injury or work-related illness that results in a lost workday is counted in the ratio. Thus, minor injuries that can be treated with first aid are not counted, but counted injuries range all the way to death. The 200,000 hours is roughly equivalent to 100 worker years. The OSHA incidence rate illustrates two features of risk measures The details of the accident are not included, and these measures can be used for non-work-related exposures. 

Statistical information on past accidents and sickness may identify unsatisfactory trends in operating procedures which can be eliminated at the design stage of safe systems of work. The use of accident statistics and rates, e.g. accident incidence rate, as a sole measure of safety performance is not recommended, however, due to the variable levels of accident reporting in work situations. Under-reporting of accidents, common in many organisations, can result in inaccurate comparisons being made between one location and another. 

Various forms of accident data are collected by organisations and a number of standards indices are used, e.g. rates of accident incidence, frequency, severity and duration. Accident data are based on information compiled from accident reports. As such, they are a reactive form of safety monitoring and should not, of course, be used as the sole means of measuring safety performance. However, they do indicate trends in accident experience and provide feedback which can be incorporated in future accident prevention strategies. The following rates are used ... 

TABLE 1.7 U.S. fatalities, nonfatal days lost (NFDL) Injuries, total accident incident rates (IRs), and severity measures for underground and surface mines by sector, 1995 (Reich and McAteer 1997a, b, c, d, e)... 

The upper control limit is three standard deviations from the mean, or 3 + (3 X 2.74), or 11.22. This is based on one year of data. If the observation period shrinks to a month, then the units of exposure go from. 4 to. 033, and the upper control limit rises to 31.60. This looks high, but how many incidents can happen in a month for the measure to remain within control limits The answer is that one accident in a month will yield a rate of 30.3 for that month, just inside the control limits. At this site, if we had two recordables in the month, we would exceed control limits. The point here is that comparing either the recordable rates of small sites or rates of larger sites computed over short periods is not very useful. If you measure two plants with 40 employees for over a year and one has a rate of 8 and the other of 0, there is no statistical basis for concluding they are different. This difference is within the normal random variation of measure being used. The incident rate of 8 took only 3 recordable events to reach. 

The most interesting problem in safety science and technology is the correct choice, which means the selection of the appropriate combination and technical level of measures to provide a level of safety accepted on commercial considerations by the suppliers, on safety grounds by the workers, and on environmental aspects by the public. Figure 20.81 shows the correlation between incident probability and consequences. If the specific hazard potential of case 2 is bigger than that of case 1, only a lower consequence grade (release rate) in case of an accident can be accepted and the consequences for case 2 have to be restricted to the site area, but for case 1, an accident consequence may be accepted outside. With respect to the safety measures necessary to reduce the incident probability to an acceptable level, the minimum safety in case 2 has to be higher than in case 1. 

When you fail to measure, track, and communicate your results, you will not know what is and is not working. Fortunately, most areas of motor carrier safety are very measurable—vehicle accidents, cargo claim incidents, retention rates, regulatory compliance, etc. 

One or more indices describing incident performance according to various units of measurement (e.g., disabling injury frequency rate, number of lost-time accidents, disabling injury severity rate, number of first-aid cases, or dollar loss). It may also refer to a summary statement describing incident performance. 

Health and safety differs from many areas measured by managers because improvement in performance means fewer outcomes from the measure (injuries or ill-health) rather than more. A low injury or ill-health rate trend over years is still no guarantee that risks are being controlled and that incidents will not happen in the future. This is particularly true in organizations where major hazards are present but there is a low probability of accidents. 

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