Risk-based approach advantages

This section provides a discussion about the differences between risk-based and compliance-based safety assurance and the efficiencies and advantages of having a risk-based approach. 

In decision-making, a reference to the advantages may lead to uncertain dangers being accepted, either implicitly or explicitly, for example because it is simply impossible or undesirable to exclude uncertain threats (too expensive, takes up too much space). The risk-based approach imphes that physical safety will in fact be violated at some point. The approach taken to incidents (Chapter 2) and damage arrangements (Chapter 4) are therefore necessary complements for a policy that focuses on risks and uncertainty. However, government must then cope with (and be able to cope with) potential violations of physical safety that should always be factored into any calculation of opportunities. The aim is... 

A risk-based approach offers significant advantages compared to the current practice. A flood-risk approach allows the choice of the safety levels to be further rationalized if the consequences of flooding and the costs of protection are made explicit. Risk-based approaches exist also in other fields where safety levels have to... 

The RCEP considered that the current risk assessment approach has the advantage of being evidence-based and transparent, but that a new approach, one that balances precaution with an evidence-based approach is needed (RCEP, 2003, p96). This suggests that precaution disregards evidence, which is not the case. Rather, it is more open to different types of evidence than the often narrow view taken by risk assessment. It considers the weight of evidence , the evidence from differ-... 

In classical risk assessment approaches the technical and economical issues are analysed with different methods. The main reason for this is, in addition to the problem to get suitable data, a methodical problem. The methods to analyse technical risks are not compatible with economical issues and vice versa. This paper compares the most common and general methods for complex data analysis and manipulation. It concludes that the Monte-Carlo-Simulation is very suitable for risk assessment issues. The MCS, based on random events, can handle almost any common information (e.g. empirical, continuous, quantative data and expert knowledge). This is one of the major advantages of the simulation method due to the fact that different kinds of information are used in technical and economical issues. To perform a risk assessment with the MCS it is suitable to use an adapted v-model to connect the technical with the economical level. To get versatile outputs, MCS can be inserted in all typical statistic methods which offer a lot of possible output visualizations. 

ML is the approach most commonly used to fit a distribution of a given type (Madgett 1998 Vose 2000). An advantage of ML estimation is that it is part of a broad statistical framework of likelihood-based statistical methodology, which provides statistical hypothesis tests (likelihood-ratio tests) and confidence intervals (Wald and profile likelihood intervals) as well as point estimates (Meeker and Escobar 1995). MLEs are invariant under parameter transformations (the MLE for some 1-to-l function of a parameter is obtained by applying the function to the untransformed parameter). In most situations of interest to risk assessors, MLEs are consistent and sufficient (a distribution for which sufficient statistics fewer than n do not exist, MLEs or otherwise, is the Weibull distribution, which is not an exponential family). When MLEs are biased, the bias ordinarily disappears asymptotically (as data accumulate). ML may or may not require numerical optimization skills (for optimization of the likelihood function), depending on the distributional model. 

This option does not appear to be advantageous for either radionuclides or chemicals that cause stochastic responses. In radiation protection, total detriment is used mainly to develop the tissue weighting factors in the effective dose (see Section 3.2.2.3.3), but ICRP and NCRP have continued to emphasize fatal responses as the primary health effect of concern in radiation protection and radiation risk assessments. Since total detriment is based on an assumption that fatalities are the primary health effect of concern, the same difficulties described in the previous section would occur if this measure of response were used for chemicals that induce stochastic responses. Other disadvantages of using total detriment include that detriment is not a health-effect endpoint experienced by an exposed individual and the approach to weighting nonfatal responses in relation to fatalities is somewhat arbitrary. Furthermore, total detriment is not as simple and straightforward to understand as either incidence or fatalities. 

There are currently two approaches for setting REIs in the United States one might be considered the past approach and the other the future approach. In the first approach, the EPA s Worker Protection Standards establish interim REIs based only on acute toxicity without any consideration of the crop, the work activity or exposure. Recognizing that risk is a product of toxicity and exposure, this approach is limited in that it only takes into account one-half of the risk equation. Nonetheless, this approach is the basis for most of the REIs currently in place in the USA. In the second approach, the EPA s re-registration process (as outlined in the Worker Protection Standards) requires the development of product, crop and activity-specific REIs based on the risk associated with any given use scenario. The advantage of this approach is that it takes into account both the toxicity and exposure components of the risk equation. Such an approach is the... 

Additional advantages of spontaneous reporting systems include the detection of extremely rare ADRs and ability to identify at-risk subgroups. In order to enhance the spontaneous reporting system approach, the FDA developed the MedWatch form. This form can be faxed to the agency (1-800-FDA-1078) or called in (1-800-FDA-1088) (40). The forms also can be obtained by the MedWatch Online internet-based website (http //www. fda.gov/medwatch/). 

---