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Title: Validation in the Absence of Observed Events

Abstract

Here our paper addresses the problem of validating models in the absence of observed events, in the area of Weapons of Mass Destruction terrorism risk assessment. We address that problem with a broadened definition of “Validation,” based on “backing up” to the reason why modelers and decision makers seek validation, and from that basis re-define validation as testing how well the model can advise decision makers in terrorism risk management decisions. We develop that into two conditions: Validation must be based on cues available in the observable world; and it must focus on what can be done to affect that observable world, i.e. risk management. That in turn leads to two foci: 1.) the risk generating process, 2.) best use of available data. Based on our experience with nine WMD terrorism risk assessment models, we then describe three best use of available data pitfalls: SME confidence bias, lack of SME cross-referencing, and problematic initiation rates. Those two foci and three pitfalls provide a basis from which we define validation in this context in terms of four tests -- Does the model: … capture initiation? … capture the sequence of events by which attack scenarios unfold? … consider unanticipated scenarios? …more » consider alternative causal chains? Finally, we corroborate our approach against three key validation tests from the DOD literature: Is the model a correct representation of the simuland? To what degree are the model results comparable to the real world? Over what range of inputs are the model results useful?« less

Authors:
 [1];  [2]
  1. Decision Strategies, LLC, New York, NY (United States)
  2. Old Dominion Univ., Norfolk, VA (United States). Virginia Modeling, Analysis and Simulation Center
Publication Date:
Research Org.:
Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1262178
Report Number(s):
LLNL-JRNL-669713
Journal ID: ISSN 0272-4332
Grant/Contract Number:  
AC52-07NA27344
Resource Type:
Accepted Manuscript
Journal Name:
Risk Analysis
Additional Journal Information:
Journal Volume: 36; Journal Issue: 4; Journal ID: ISSN 0272-4332
Country of Publication:
United States
Language:
English
Subject:
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE; Validation; WMD Terrorism Risk Assessment; WMD Terrorism Risk Management

Citation Formats

Lathrop, John, and Ezell, Barry. Validation in the Absence of Observed Events. United States: N. p., 2015. Web. doi:10.1111/risa.12442.
Lathrop, John, & Ezell, Barry. Validation in the Absence of Observed Events. United States. https://doi.org/10.1111/risa.12442
Lathrop, John, and Ezell, Barry. Wed . "Validation in the Absence of Observed Events". United States. https://doi.org/10.1111/risa.12442. https://www.osti.gov/servlets/purl/1262178.
@article{osti_1262178,
title = {Validation in the Absence of Observed Events},
author = {Lathrop, John and Ezell, Barry},
abstractNote = {Here our paper addresses the problem of validating models in the absence of observed events, in the area of Weapons of Mass Destruction terrorism risk assessment. We address that problem with a broadened definition of “Validation,” based on “backing up” to the reason why modelers and decision makers seek validation, and from that basis re-define validation as testing how well the model can advise decision makers in terrorism risk management decisions. We develop that into two conditions: Validation must be based on cues available in the observable world; and it must focus on what can be done to affect that observable world, i.e. risk management. That in turn leads to two foci: 1.) the risk generating process, 2.) best use of available data. Based on our experience with nine WMD terrorism risk assessment models, we then describe three best use of available data pitfalls: SME confidence bias, lack of SME cross-referencing, and problematic initiation rates. Those two foci and three pitfalls provide a basis from which we define validation in this context in terms of four tests -- Does the model: … capture initiation? … capture the sequence of events by which attack scenarios unfold? … consider unanticipated scenarios? … consider alternative causal chains? Finally, we corroborate our approach against three key validation tests from the DOD literature: Is the model a correct representation of the simuland? To what degree are the model results comparable to the real world? Over what range of inputs are the model results useful?},
doi = {10.1111/risa.12442},
journal = {Risk Analysis},
number = 4,
volume = 36,
place = {United States},
year = {Wed Jul 22 00:00:00 EDT 2015},
month = {Wed Jul 22 00:00:00 EDT 2015}
}

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Works referenced in this record:

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  • Ezell, Barry Charles; Winterfeldt, Detlof von
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Towards a practical method to validate decision support systems
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Modelling blast loads on buildings in complex city geometries
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