Proficiency-testing scoring system

Proficiency testing can be assessed in different ways. One of the most used evaluation system is that of so-called z-scores which are defined as follows (Lawn et al. [1993] Thompson and Wood [1993]) ... 

There are a number of different performance scoring systems used in proficiency testing schemes. The most commonly used system is the z-score, which... 

In Section 7.3.3, we learned about one of the most common scoring systems used in proficiency testing - the z-score - and how laboratory performance can be judged as being satisfactory, questionable or unsatisfactory. How should a laboratory act on the performance scores it receives Action should be considered in the following situations ... 

Participation in proficiency tests is not a prerequisite or an absolute substitute for IQC measures or vice versa. However, participance in proficiency tests is meaningless without a well-developed IQC system. IQC underlies participance in PT schemes, while IQC and participance in PT schemes are both important substitutes of AQA (Figure 6). It is shown that laboratories with the strongest QC procedures score significantly better in PT schemes [8,50]. Participance in PT can to a certain extent improve the laboratory s performance however unsatisfactory performance in schemes (up to 30% of all participants) has been reported. This means that there... 

The sum of all points scored eventually represents a laboratory s performance in a single proficiency test. The maximum achievable points, however, depends on the total number of spiking chemicals used. As this number varies from test to test, the points scored cannot be used to compare performances between laboratories participating in different proficiency tests. This comparison is achieved with the final letter scoring system, and is shown in Table 9. 

Table 9. Scoring system of the OPCW proficiency-testing scheme...

The range for scoring varies from A (i.e. maximum score) to F (i.e. failure of the test). This A, B, C... system allows for comparison of performance in a number of different proficiency tests, in a rather simple and unambiguous way. However, in combination with the previously discussed strict penalty system, the simplicity of this letter system is at the expense of its transparency letter scores below the maximum score A do not reflect the type of error(s) made. 

One of the most widely used and simplest scoring systems used in PT schemes is the Z score. Z score is defined as a performance score recommended for use in proficiency testing schemes to evaluate the accuracy of the analytical results submitted by participating laboratories. ... 

The Facility Supervisor and Hot Cell Operators are qualification positions requiring successful completion of a formal training program before an individual Is allowed to operate specific HCF equipment and/or controls unsupervised. Proficiency for the qualified positions is demonstrated by minimum acceptable scores on written tests and by observation of the individual s operating skill with manipulators, production process equipment, and plant safety equipment and safety systems. Qualification also requires demonstrated adherence to conduct of operations principles, ability to follow procedures, and commitment to cultivating an environment of teamwork and continuous improvement. Staff contributions to improvement of procedures and processes are actively encouraged as a way to enhance the safety and work culture. 

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