Skill-Based

A relatively simple model has been developed by Rasmussen to quantify human error rates based on the level of training (Rasmussen (1979, 1981)). This model divides the behaviour into three basic categories skill-based, rule-based, and knowledge-based behaviours. 

Skill-based behaviours depend mostly on the operator s practice in performing the task. In short the operator can perform the task without ambiguity. A simplistic view is that skill-based errors are slips or hrpses. These errors tend to be related to highly routine activities in familiar circumstances omissions, repetitions, reversals, interference errors and double-capture slips. An example is incorrect use of foot pedal controls of fork-lift trucks. Some fork-lift trucks 

Rule-based behaviour is at work when the operator does not have the same level of practice at performing the required task, but has a clear knowledge of the procedures. There may be some hesitation in recalling any procedure, the procedure may not be carried out in the proper sequence, or any step may not be performed precisely. 

Rule-based errors are concerned with the misapplication or inappropriate use of problem solving rules. Individuals have a complex array of specific and general rules that they use to deal with everyday problems. Rules are of the type i/ event then action . Some simplistic examples relating to the operation of vehicles are  

This is a perfectly good rule under most circumstances. However, with accidents involving contact with high voltage overhead lines, remaining in the cab provides protection against electrocution (principle of the Faraday Cage). A better additional rule would be  

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KNOWLEDGE-BASED MODE SKILL-BASED MODE... 

If, as a result of applying the action rule, the problem is solved, the worker will then return to the original skill-based sequence. If the problem is not resolved, then further information may be gathered, in order to try to identify a pattern of symptoms corresponding to a known cause. 

In Figure 2.6, the slips/mistakes distinction is further elaborated by relating it to the Rasmussen SRK classification of performance discussed earlier. Slips can be described as being due to misapplied competence because they are examples of the highly skilled, well practiced activities that are characteristic of the skill-based mode. Mistakes, on the other hand, are largely confined to the rule and knowledge-based domains. 

In the skill-based mode, recovery is usually rapid and efficient, because the individual will be aware of the expected outcome of his or her actions and will therefore get early feedback with regard to any slips that have occurred that may have prevented this outcome being achieved. This emphasizes the role of feedback as a critical aspect of error recovery. In the case of mistakes, the mistaken intention tends to be very resistant to disconfirming evidence. People tend to ignore feedback information that does not support their expectations of the situation, which is illustrated by case study 1.14. This is the basis of the commonly observed "mindset" syndrome. 

If the nature of the problem is not readily apparent, then it might be necessary to go to the rule-based level. In this case a diagnostic rule will be applied to identify the state of the plant and an action rule used to select an appropriate response. Control will revert to the skill-based level to actually execute the required actions. More abstract functions such as situation evaluation and planning will only be required at the knowledge-based level if the problem cannot not be resolved at the rule-based level. 

The lighter arrows represent typical shortcuts, which omit particular stages in the information-processing chain. These shortcuts may be "legitimate," and would only lead to errors in certain cases. For example, the worker may erroneously believe that he or she recognizes a pattern of indicators and may immediately execute a skill-based response, instead of moving to the rule-based level to apply an explicit diagnostic rule. 

The dotted lines in the diagram indicate the various feedback paths that exist to enable the individual to identify if a particular stage of the processing chain was executed correctly. Thus, if the operating team had planned a strategy to handle a complex plant problem, they would eventually obtain feedback with regard to whether or not the plan was successful. Similar feedback loops exist at the rule and skill-based levels, and indicate opportunities for error correction. The application of the stepladder model to a process industry example is given in Appendix 2A at the end of this chapter. 

Skill-based Errors manual variability strong but wrong action sequences Train for physical and manipulative skills (repeated practice and feedback) Checklists setting out starting and finishing activities and checks Layout and labeling of controls and process lines Distinguish tetween plant areas with similar appearance but different functions Provide feedback... 

This box, which is self-explanatory, involves highly practiced actions in the skill-based domain. 

It can be seen that the various boxes in the flowchart can be associated with different stages of the stepladder model. For example, the first box on the left corresponds to skill-based behavior and its associated internal failure mechanisms. The second box illustrates the situation (Stereotype Fixation) where the worker erroneously does not change to a rule-based mode when encountering an unusual situation in the skill-based mode (see also the discussion of the GEMS model in Section 2.6.3). 

Experience and familiarity with the task will affect the relationship between temperature and performance. Experience and practice will make performance largely skill based, and therefore, more resistant to impairments due to high temperatures. This explains why unskilled workers are affected more adversely when they have to work in extreme heat. 

The practical implications of this experiment are that when evaluating the effects of shift work due to circadian effects, the type of task being carried out by the worker must be taken into account. For example, skill-based tasks would be expected to exhibit the performance changes characteristic of low memory load tasks, whereas performance variations in knowledge-based tasks would be expected to follow the pattern of high memory load tasks. Performance on rule-based tasks may depend on the degree of frequency of use of the rules, which in turn may determine the memory load. If these results were confirmed by further process plant studies, it would have implications for when different types of operation (involving different levels of memory load) should be scheduled to reduce circadian rhythm effects and minimize errors. 

Advocates of the global approach would argue that human activities are essentially goal-directed (the cognitive view expressed in Chapter 2), and that this cannot be captured by a simple decomposition of a task into its elements. They also state that if an intention is correct (on the basis of an appropriate diagnosis of a situation), then errors of omission in skill-based actions are imlikely, because feedback will constantly provide a comparison between the expected and actual results of the task. From this perspective, the focus would be on the reliability of the cognitive rather than the action elements of the task. 

Skill-Based Level of Control A mode of information processing characterized by the smooth execution of highly practiced, largely physical actions requiring little conscious monitoring. 

Slips Errors in which the intention is correct but failure occurs when carrying out the activity required. Slips occur at the skill-based level of information processing. 

Advanced Higher Chemistry is a challenging, but rewarding, course, it has been devised to allow you to develop the ability to think analytically, creatively and Independently, and to make reasoned evaluations. The course emphasises practical and experiential learning opportunities with a strong skills-based approach. 

Skill-based At the lowest level, these are routine skills of observation, hand-eye coordination, and control skills. Skills also include pattern recognition and actions that are manual, well known, and... 

People pursuing jobs in the 30,000 to 40,000 salary range are typically the group with negative information in their employment history that needs to be dealt with effectively in a resume. When someone has negative information or a lack of work experience, I tend to focus on creating a skill-based resume. 

In this situation, the skill headings used within the resume become extremely important. I recommend that someone who needs a skill-based resume find at least five to ten help-wanted ads for job openings they d be interested in filling. By reviewing those ads, the job seeker should be able to create a comprehensive list of skills to focus on within their resume. 

The skills base for business development has three distinct areas knowledge, analysis and communication. 

There are, arguably, two reasons why skill-based assessments are hidden or ignored in tourist behaviour research. One view is that much tourist behaviour is gaze oriented, a simple observing of the visited scenes and communities and so participants are not differentiated by the concept of skill. Similarly Rojek and Urry (1997a) observe that sometimes tourists take photos simply because, confronted with remarkable vistas and sights, they simply do not know what else to do. 

The issue of the level of skills can also be seen as partly embedded in a differently labelled tradition of research already reported in Chapter 2. Attention has been directed to the influence of specialisation or levels of previous experience in understanding tourist behaviour (Cole Scott, 2000 McFarlane, 1994 Martin, 1997). It is certainly possible to see that more experienced travellers and those who specialise in activities are more likely to have a higher skill base. 

Designing a new drag is an application of the Craft pharmaceutical) skill. It functions exactly like any other Craft skill, based off of the following table. 

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