Risk scoring systems

Preventing CIN is of particular importance in patients with diabetes and chronic kidney disease, as these are two of the most powerful independent risk factors for CIN (77), Diabetics are more susceptible to (CIN) than are the nondiabetics, and diabetics with pre-existing chronic kidney disease (CKD) are at even greater risk (78). In a recently proposed CIN risk-scoring system, patient characteristics such as diabetes, age >75, chronic congestive heart failure, admission with acute pulmonary edema, hypotension, anemia and chronic kidney disease and various procedure-related characteristics including increasing volumes of contrast media, and intra-aortic balloon pump use were all found to reliably contribute to increased risk (79). 

Users of (risk scoring) systems should be inquisitive and cautious concerning their content, the meanings of the terms adopted, the numericals applied to the gradations within elements to be scored, and how they are applied in determining risk levels. 

The numbers assigned to the elements to be scored are entirely judgmental, have no basis in fact or good science, and vary for the same subject in different systems. There are no universally applied rules to assign value numbers to elements to be scored. All values in risk scoring systems reflect the experience and views of those who create the system. 

Meanings of the terms probabihty, likelihood, frequency of exposure or endangerment, and severity as used in risk scoring systems are not consistent. Also, it may be that within a system a term may appear more than once and have different usages and consistency in the meanings of the terms used initially in the system may not be maintained. 

If risk-scoring systems are apphed rigidly whereby a higher score indicates a greater risk than a lower score, and the scores are not considered in light of the employee, conununity, social, and financial concerns of the organization, its best interests may not be weU served. This applies especially to low probability events that may have severe consequences, for which risk scores may be low [p. 171]. 

Intelligent use of this risk scoring system is proposed, Users of it should recognize that the risk assessment process is as much art as science and that the statistical outcomes derived from its application are to be just one element in the decision-making. 

Risk is determined by assessing its two components the severity of harm or damage resulting from a hazard-related event and the probability that the event could occur. Table 15.1 presents a sample Risk Assessment Matrix, illustrating how these two factors are combined to obtain a risk level. A review of the many published risk assessment matrices appears in chapters titled A Primer On Hazard Analysis And Risk Assessment and Risk Scoring Systems in this authors book titled Innovations In Safety Management. 

Vreeburg EM, Terwee CB, Snel P, et al. (1999) Validation of the Rockall risk scoring system in upper gastrointestinal bleeding. Gut 44 331-335... 

Three and Four Dimensional Numerical Risk Scoring Systems... 

Some risk assessment systems include numerical categories for probability and severity levels and computations are made to arrive at a number that determines the risk level. Arriving at those numerical categories is entirely judgmental. Some of those numerical risk assessment systems are discussed in Chapter 10, Three-and Four-Dimensional Numerical Risk-Scoring Systems. ... 

For this primer, two-dimensional risk assessment matrices are discussed. They are displays of variations for two categories of terms the severity of harm or damage that could result from a hazards-related incident or exposure, and the probability that the incident or exposure could occur. They also show the risk levels that derive from the various combinations of severity and probability. A review of three- and four-dimensional risk assessment systems is given in Chapter 10, Three- and Four-Dimensional Numerical Risk-Scoring Systems. ... 

Take care, though-arriving at the values shown in this matrix is a qualitative exercise. And that is the case for all risk scoring systems that are not based on hard probability and severity numbers, which rarely are available. 

TABLE 9 Risk-Scoring System ANSI/PMMI B155.1-2006... 

In Chapter 10, Three- and Four-Dimensional Numerical Risk-Scoring Systems, comment is made on FMEA publications issued for the semiconductor industry by International SEMATECH and for the auto industry by the Automotive Industry Action Group. 

B155.1 s Subsection 6.4, Assess Initial Risk, says that risks shall be assessed using a risk scoring system. The Example Risk-Scoring System shown in the standard is taken from MIL-STD-882D. It is identical to the Risk Assessment Matrix depicted in Table 7 in Chapter 8, A Primer on Hazard Analysis and Risk Assessment, and shown here as Table 4. 

THREE AND FOUR DIMENSIONAL NUMERICAL RISK SCORING SYSTEMS... 

However, the world of risk assessment is in transition. Some systems now in use are three- or four-dimensional, and they require numerical risk scorings. Safety professionals can expect that variations of numerical risk scoring systems will proliferate. Nevertheless, it needs to be said that two-dimensional, qualitative risk assessment systems are not obsolete. Often, a two-dimensional system will be selected because it is sufficient for the hazards and risks encountered and it works well within an organization. This chapter will inform safety professionals on ... 

Three-dimensional numerical risk scoring systems... 

An extended three-dimensional numerical risk scoring system that includes a method to justify the risk amelioration costs in relation to the amount of risk... 

A four-dimensional numerical risk scoring system... 

A numerical risk-scoring system that this author developed... 

Similarly, some engineers are using numerical risk scoring systems to meet the risk assessment requirements placed on manufacturers who sell machinery to countries in the European Community. One such system in use for that purpose is four-dimensional. Also, a three-dimensional numerical risk-scoring system is in use in a segment of the heavy machinery manufacturing industry. It was introduced by engineering personnel to meet the demands for product safety. 

Substantial variations exist in the elements to be scored in the three-dimensional and the single four-dimensional numerical risk scoring systems to be reviewed here. To begin the discussion, excerpts are taken from the National Safety Council s (NSC s) Accident Prevention Manual Administration Programs, Twelfth Edition, and appear here with permission. 

In the process, for each identified hazard, numerical scorings as follows are given to Severity, Exposure, and Probability. It is significant that they are totaled to arrive at a final rating, not multiplied in sequence as is the case in other three- and four-dimensional risk-scoring systems. Thus, the status of the severity... 

THREE AND FOUR DIMENSIONAL NUMERICAL RISK SCORING SYSTEMS TABLE 4 Suggested Design FMEA Severity Evaluation Criteria ... 

In SEMATECH s FMEA, three criteria must be numerically ranked Severity, Occurrence, and Detection. This is how they are defined in the Guide. As was stated earlier in this chapter, definitions of the terms used in risk-scoring systems vary, and the definitions in this system have their own unique characteristics. 

This is the risk scoring system Risk Score = Severity x Frequency x Vulnerability Risk Score = S x F x V... 

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