Human error rights

A probabilistic statement of the likelihood of human-error events presents each error in the task analysis as the right limb in a binary branch of the HRA event tree. These binary branches form the chronological limbs of the HRA event tree, with the first potential error siai ting from the highest point on the tree. (Figure 4.5-4). Any given [ask appears as a two-limb branch the left limb represents the probability of success the right limb represents the probability of failure. 

This chapter has provided an overview of a recommended framework for the assessment of human error in chemical process risk assessments. The main emphasis has been on the importance of a systematic approach to the qualitative modeling of human error. This leads to the identification and possible reduction of the human sources of risk. This process is of considerable value in its own right, and does not necessarily have to be accompanied by the quantification of error probabilities. 

People expect the hot water tap to be on the left side and the cold water on the right side. When this is not the case, they are confused and make mistakes. Rising-stem gate valves are expected to close if the handle is turned in a clockwise rotation and open if turned counter clockwise. When this does not happen, we must mentally compensate. We then have a tendency to make an error, particularly when under stress or during an emergency. Deviating from normal convention, expected actions, and established habits can be an underlying cause of human error. 

The risk assessment process can be conducted by examining record types to see if they are GxP or non-GxP, and then applying severity checks, likelihood, and probability of detection criteria, as illustrated in Figure 15.2. The most severe scenarios shonld be linked to direct patient/consnmer impact. GxP noncompliance and broken license conditions are severe in their own right bnt not as critical as patient/consumer health in this analysis." Its likelihood will be influenced by the degree of human error in how the record is input and used. The probability of detection needs to take into account the probability of the impacted record being used. Once failure modes are understood, then the appropriate design controls can be introduced. These should be documented and validated as part of the computer system life cycle discussed earher in this book. 

It is easy to blame accidents on human error, but good design can often minimize this.161 Avoid poor lighting or contrast. Provide a checklist so that the operator will find it easy to recall all of the necessary information. Most valves have right-handed threads. Do not mix in any that have left-handed threads. Mount them so that they are easy to access, and the labels are easy to see. 

In the case of removable and re-attachable systems, the right balance between ease of attachment and security of the sensor(s) need to be reached. As the wearer could be stretching the textile to its limit, the movement must not cause the sensing system to fall off. At the same time, the insertion and removal of the sensors must not take long, nor be too complicated such that human error occurs easily, nor must it require any special tools. 

Human errors can be reduced substantially by making human factors an integral part of the medical device/equipment development process (i.e., right from the concept phase to the production phase) as shown in Figure 9.2 [24],... 

Human reliability analysis is an important component of risk analysis. Reviews of past accidents show that human error accounts for the vast majority of these events. The technique most widely used for estimating human error probabilities is called THERP (Swain and Guttman, 1983). The method uses event trees drawn in a different format to arrive at a human error probability. See Fig. 10.15 for an example. In these event trees, failure paths branch right and success paths branch left. 

And something that has happened to aU of us, we put money in the coffee machine, the cup falls into place, but at an angle, the coffee flows past the cup into the drain. But we cannot open the little window to right the cup until the coffee has finished dispensing (presumably so that we do not bum our hands on the hot coffee). AU of these are hnman factors mistakes. Interestingly enough, each of those human errors could have been avoided if the design had better considered how people would use the equipment. 

The futility of using human error to explain accidents can be demonstrated by the following argument, cf.. Figure 4.9. If we consider a safe system to be one where the probability of failure is low, e.g., 10 then there will be at least 99,999 cases of acceptable performance for every case of unacceptable performance. In other words, accidents will be quite rare. But if the so-called human error is the cause of the event that goes wrong, then what is the cause of all the other events that go right The only reasonable answer is humans humans try to make sure that their actions... 

First, Bahners does not make clear how an intention to agitate can be recognized, if not by errors of form. It is stated in the German constitution that science is free without restriction. Decisions of the German Federal Constitutional Court have stated that science is defined by formal rules alone and not by content. These decisions are in agreement with fundamental theoretical works on the nature of scientific knowledge. If Bahners thinks differently, he is anti-constitutional, anti-scientific, and anti-human rights. 

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