Subject wrong measurement

The research described in this thesis deals with safety management in complex and high-risk organizations. Companies in the chemical process industry handling hazardous substances are chosen as the subject of study. In particular this thesis will focus on the current safety indication process, and how this safety indication process works and its shortfalls. An unreliable indication process, leads automatically to wrong reactions and measures to prevent possible accidents. Increased understanding of this process helps in providing a better basis from which effective measures to prevent accidents can be derived. 

Have we included all the necessary safeguards Is the information we plan to provide to the volunteer sufficiently detailed How can we be sure that he or she really understands the purpose of the study Should we include a test to confirm that the subject knows exactly what measurements we will be using, how often they will take place, how long they will take and what might go wrong ... 

Statistical testing operates in what at first seems a rather perverse manner. Suppose you think a treatment has an effect. The theory you actually test is that it has no effect the test tells you how improbable your data would be if this theory were true. This no effect theory is the null hypothesis (NH). If your data are very improbable under the NH, then you may suppose it to be wrong, and this would support your original idea (the alternative hypothesis ). The concept can be illustrated by an example. Suppose two groups of subjects were treated in different ways, and you observed a difference in the mean value of the measured variable for the two groups. Can this be regarded as a true difference As Fig. 41.1 shows, it could have arisen in two ways ... 

In the simplest case of parallel-group study, a group of patients presenting sequentially are randomized to one of two equally sized treatment groups, until a prospectively determined total number of patients has been recruited. All these patients are followed for a predetermined period of time, or until some end point is achieved. The database is quality assured and locked before the randomization code is broken. The patients are then sorted according to their treatment, the end point measurements are subjected to a statistical test and an interpretation of the effect (or absence thereof) of the drug is made. What could possibly go wrong ... 

This incomplete discussion of the effect of capacities in and around a conductance cell is included to indicate the nature of the errors which may be encountered with improperly designed cells. Similar errors may arise from wrongly arranged Wheatstone bridges. Careful conductance measurements should not be attempted without an understanding of the phenomena connected with alternating currents. The author has somewhat reluctantly left out a more complete discussion of the subject. 

The direct experimental result of a crystallographic analysis is an electron-density map, and not the atomic model everybody looks at If errors occur in crystal structures, they most often occur at the level of the (subjective) interpretation of the electron-density maps by the crystallographer. A severe problem, especially at low resolution (lower than 3.0 A), is the so-called model bias. To calculate an electron-density map, one needs amplitudes and phases. The amplitudes are determined experimentally, but the phases cannot be measured directly. In later stages of refinement, they are calculated from the model, which means that if the model contains errors, the phases will contain the same errors. Since phases make up at least 50% of the information which is used to calculate the electron-density maps, wrong features may still have reasonable electron density because of these phase errors. 

According to the model of safe behavior, the unsafe behavior of the people and subject are the causes for the accident together. Accident statistics show that in the world, 70% 80% have a direct link to human wrong and unsafe operation. It is one of the important hazards to people s life and seriously endanger the normal operation of production and operation enterprises Lut-ness even said that 95% of accidents are caused by people s unsafe behaviors - In China, coal mines for unsafe operation behavior is also an important cause of the accident, 97.67% are caused by people s unsafe behavior. So how to take effective measures to control the happening of unsafe behavior is the most important thing. 

There is too often a blame culture. When things go wrong, the response is to seek one or two individuals to blame, who may then be subject to disciplinary measures or professional censure. That is not to say that in some circumstances individuals should not be held to account, but as the predominant approach this acts as a significant deterrent to the reporting of adverse events and near misses (Department of Health, 2000, p. 77). 

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