Validation ‐ Another Perspective

McCombie, Charles; McKinley, Ian G.

doi:10.1111/j.1745-6584.1993.tb00583.x

Cited by 14 publications

(5 citation statements)

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“…During the different phases of the trial, the plaintiff's attorney used Bredehoeft and Konikow's (1993) arguments that groundwater models cannot be validated, only invalidated. Bair (1994) mentioned that his response, which was against this argument, was supported by McCombie and McKinley (1993) and de Marsily et al's (1992) comments on Bredehoeft and Konikow's (1993) arguments. Summarizing Bair's (1994) conclusions about this experience, it shows how the jury understood the difference between predictions that are certain beyond reasonable doubt (operational or confidence-based validity) and predictions that are certain beyond any doubt (strictest form of validity).…”

Section: Philosophical Views Of Model Validationmentioning

confidence: 83%

“…They, however, caution that care should be taken to predict only for a time comparable to the period that was matched. McCombie and McKinley (1993) argue against these views and assert that the key problem in the validation issue is to define what level of accuracy and what degree of confidence must be achieved in the prediction of specific parameters. The decision about how much effort must go into the validation process before the model can be considered to be valid is necessarily subjective and very dependent on the complexity of the system and on the objective of using the model in the first place.…”

Section: Philosophical Views Of Model Validationmentioning

confidence: 99%

“…More background details are given in the Appendices regarding goodness-of-fit measures and hypothesis testing. McCombie and McKinley (1993) argue that the decision about how much effort must go into the validation process before the model can be considered to be valid is necessarily subjective and very dependent on the complexity of the system and on the objective of using the model in the first place. They further recommend that the subjective aspect of assessing if a model is good enough be included in the term "validation."…”

Section: Subjective Versus Objective Judgmentmentioning

confidence: 99%

“…The decision about how much effort must go into the validation process before the model can be considered to be valid is necessarily subjective and very dependent on the complexity of the system and on the objective of using the model in the first place. McCombie and McKinley (1993) further recommend that the subjective aspect of assessing if a model is good enough be included in the term "validation." de Marsily et al (1992) present evidence from their modeling experience as proof that their groundwater model has been validated or at least proven to be not invalid.…”

Section: Philosophical Views Of Model Validationmentioning

confidence: 99%

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A Validation Process for the Groundwater Flow and Transport Model of the Faultless Nuclear Test at Central Nevada Test Area

Hassan¹

2003

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EXECUTIVE SUMMARYMany sites of groundwater contamination rely heavily on complex numerical models of flow and transport to develop closure plans. This has created a need for tools and approaches that can be used to build confidence in model predictions and make it apparent to regulators, policy makers, and the public that these models are sufficient for decision making. This confidence building is a long-term iterative process and it is this process that should be termed "model validation." Model validation is a process not an end result. That is, the process of model validation cannot always assure acceptable prediction or quality of the model. Rather, it provides safeguard against faulty models or inadequately developed and tested models. Therefore, development of a systematic approach for evaluating and validating subsurface predictive models and guiding field activities for data collection and long-term monitoring is strongly needed. This report presents a review of model validation studies that pertain to groundwater flow and transport modeling. Definitions, literature debates, previously proposed validation strategies, and conferences and symposia that focused on subsurface model validation are reviewed and discussed. The review is general in nature, but the focus of the discussion is on site-specific, predictive groundwater models that are used for making decisions regarding remediation activities and site closure. An attempt is made to compile most of the published studies on groundwater model validation and assemble what has been proposed or used for validating subsurface models. The aim is to provide a reasonable starting point to aid the development of the validation plan for the groundwater flow and transport model of the Faultless nuclear test conducted at the Central Nevada Test Area (CNTA).The review of previous studies on model validation shows that there does not exist a set of specific procedures and tests that can be easily adapted and applied to determine the validity of site-specific groundwater models. This is true for both deterministic and stochastic models, with the latter posing a more difficult and challenging problem when it comes to validation. This report then proposes a general validation approach for the CNTA model, which addresses some of the important issues recognized in previous validation studies, conferences, and symposia as crucial to the process. The proposed approach links model building, model calibration, model predictions, data collection, model evaluations, and model validation in an iterative loop. The approach focuses on use of collected validation data to reduce model uncertainty and narrow the range of possible outcomes of stochastic numerical models. It accounts for the stochastic nature of the numerical CNTA model, which used Monte Carlo simulation approach. The proposed methodology relies on the premise that absolute validity is not even a theoretical possibility and is not a regulatory requirement. Rather, it highlights the importance of testing as many aspect...

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Section: Philosophical Views Of Model Validationmentioning

confidence: 83%

Section: Philosophical Views Of Model Validationmentioning

confidence: 99%

Section: Subjective Versus Objective Judgmentmentioning

confidence: 99%

Section: Philosophical Views Of Model Validationmentioning

confidence: 99%

See 2 more Smart Citations

A Validation Process for the Groundwater Flow and Transport Model of the Faultless Nuclear Test at Central Nevada Test Area

Hassan¹

2003

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“…It is now generally accepted that such a distinction is untenable in its extreme form. Also, there is now a considerable literature suggesting that it is not only the general public who might exhibit systematic biases: experts may do so as well (Watson, 1981;Janis, 1982;Henrion and Fischoff, 1986;Fischoff, 1989;Yates, 1990;Bredehoeft and Konikow, 1993;McCombie and McKinley, 1993;Bragg, 1996;IAEA, 1997;IAEA/BIOMASS, 1998;Bell and Wilson, 2001;SKB, 2004). In this light, and since laymen in each specific case carry the burden of potential and real environmental damage, they have the right to be involved in the decision-making process.…”

Section: Influence Of Uncertainty Of Environmental Evaluations On Thementioning

confidence: 96%

An Experiment in Participative Environmental Decision Making

2006

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The paper presents a method of participatory decision-making involving the authorities at local level, experts and the public. It studies how to solve the problems caused by the heterogeneity of the parties taking part in the decision-making process. The method builds on mutual learning and consideration among the participants following a systematic approach led by a moderator. The method was tested at a workshop simulating a real-life situation. The test case studied at the workshop was the problem of identifying the best site for a low and intermediate level radioactive waste repository among three alternatives. The learning phase was the Krško Nuclear Power Plant cooling problem. The results show that the participants were able to reach agreement on the prioritisation of the alternatives and to end up with suprisingly complex and fully reasonable decision models. We believe that this was achieved particularly due to the well defined procedure that guided the decision-making process, and the ability of all participants to see the influence of their views on the decision model.

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Engineering Approach

Gorokhovski

2014

Effective Parameters of Hydrogeological Models

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Validation ‐ Another Perspective

Cited by 14 publications

References 0 publications

A Validation Process for the Groundwater Flow and Transport Model of the Faultless Nuclear Test at Central Nevada Test Area

A Validation Process for the Groundwater Flow and Transport Model of the Faultless Nuclear Test at Central Nevada Test Area

An Experiment in Participative Environmental Decision Making

Engineering Approach

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