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Willy Aspinall (Bristol) - Expert elicitation of scientific uncertainties using Cooke's Classical Model: applicability to COVID-19 risk assessments

Wednesday 10th June 2020 - 14:05 to 14:35
INI Seminar Room 1

Many COVID-19 research projects have elements of
forecasting, planning and urgent decision-making that must be executed before
solid data are available. Some
approaches, which neglect formal uncertainty quantification, can compromise
estimates of low-probability/high-consequence outcomes: this could be a
critical flaw when evaluating complex COVID-19 risks. Adopting a structured elicitation procedure
can reduce risk assessment weaknesses associated with inappropriate and sometimes
misleading parameter and modelling assumptions. Several varieties of expert
elicitation are practised, often categorised as 'behavioural aggregation' or
'mathematical aggregation'. Cooke's
Classical Model is of the latter class and we have used it extensively to
provide scientific support for critical public safety decisions during volcanic
eruptions. The method has garnered a track record for formalising the
determination of input variable or parameter uncertainty distributions for risk
modelling when conventional data do not exist or are undependable, e.g. with
the adaptive Bayes Belief Net formalism for combining disparate strands of
uncertain scientific evidence. The
underpinning algorithm provides empirical control on expert performance scoring
and weighting for combining experts’ judgments into an auditable, rational
consensus. While it has become an
established and validated elicitation procedure in many disciplines, this
approach has not found widespread use in epidemiological modelling, even though
it is well-suited to risk issues relating to emergent zoonoses. We briefly summarise the principles of the
method and how it is applied to real-world critical decision problems,
mentioning a few case studies closely analogous to the present coronavirus


The best
link to materials relevant to my talk is Roger Cooke’s website:

It has a
lot of relevant stuff, and includes a link to a video of a 1-hour talk on the
Classical Model for Structured Expert Judgment, which I gave at CDC Atlanta in
May 2107.

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Presentation Material: 
University of Cambridge Research Councils UK
    Clay Mathematics Institute London Mathematical Society NM Rothschild and Sons