1. Lynn H. Pottenger, PhD, DABT The Dow Chemical Company
Communication of Uncertainty in Hazard & Risk Assessment: Panel Discussion
Lynn H. Pottenger, PhD, DABT
The Dow Chemical Company

2. Uncertainty Workshop Focus:
Focus on identification of sources & communication of uncertainty in a risk assessment
Not how to measure
Not quantitative analysis methods
Uncertainty is inherent—but sources differ:
Data-related
Derivation of risk estimates
How best to communicate this inherent uncertainty?
Different types (sources; magnitudes)
Different impact on results of assessment
Different audiences
Different approaches to presenting/communicating uncertainty
LHP 3/24/2015
2015 SOT: Communication of Uncertainty in Hazard & Risk Assessment

3. 2015 SOT: Communication of Uncertainty in Hazard & Risk Assessment
Key Aspects
Transparent
Identify & characterize key decisions and their impact
Comprehensible
Simplify complex concepts
Useful
Geared towards identified audience
LHP 3/24/2015
2015 SOT: Communication of Uncertainty in Hazard & Risk Assessment

4. This Workshop examined four approaches:
Comparing Values to Other Peer Reviewed Numbers
Presenting Toxicological Information Visually in the Context of Alternative Values, Exposure Levels, and Biomonitoring Equivalents
Unpacking Toxicity Assessments to Understand & Improve Confidence
Improving Transparency in Dose-Response Decision Making
LHP 3/24/2015
2015 SOT: Communication of Uncertainty in Hazard & Risk Assessment

5. Comparison of Risk Values
Provides high level cross-assessment comparison of risk estimates
Deeper drill on specifics possible
LHP 3/24/2015
2015 SOT: Communication of Uncertainty in Hazard & Risk Assessment

6. Visualization of Tox/Risk/Uncertainty Information
The dose-response point that marks the beginning of a low-dose extrapolation. This point can be the lower bound estimate on dose for an estimated incidence or a change in response level from a dose-response model (BMD), or a NOAEL or LOAEL for an observed incidence, or change in level of response.
Oral Noncancer Basic Figure
Point of Departure (POD)
The range for the values are not on scale but are allowing the visualization of the uncertainty between the POD and the risk value.
Uncertainty Factors can range from 0 to 3000 (maximum). The possible types of UFs are: interspecies uncertainty (UFA); intraspecies variability (UFH); subchronic to chronic extrapolation (UFS); use of a LOAEL in absence of a NOAEL (UFL); database incomplete (UFD)
Uncertainty Factor (UF)
Dose (mg/kg/day)
An estimate of an exposure for a given duration to the human population (including susceptible subgroups that is likely to be without an appreciable risk of adverse health effects over a lifetime. It is derived from a BMDL, NOAEL, LOAEL or suitable point of departure, with uncertainty/variability factors applied to reflect limitations of the data used. Durations include acute, short-term, subchronic, and chronic and are defined individually in this glossary.
Reference Value
The shading in the figure represents a decrease in the value and the potential risk of effects; higher value (darker shade) to a lower value (lighter shade).
Focus on visualization of range between POD and risk estimate
Exposure context possible with inclusion of BE
Cross-assessment comparison possible
LHP 3/24/2015
2015 SOT: Communication of Uncertainty in Hazard & Risk Assessment

7. Confidence Scoring of 8 Elements
Focus on individual assessment
Potential to score different elements
Includes consideration of confidence
LHP 3/24/2015
2015 SOT: Communication of Uncertainty in Hazard & Risk Assessment

8. Improving Transparency: key decisions & impact
Detailed focus on individual assessment
Analysis of key decisions—data and other; distinguishes science from policy
LHP 3/24/2015
2015 SOT: Communication of Uncertainty in Hazard & Risk Assessment

9. Four new approaches and EPA/IRIS current one
ACC ARASP workshop approaches:
From cross-assessment, more general to more & more detailed, focused on a single assessment
From tabular to figures to combined
Only one addresses exposure issues
Example of EPA/IRIS current practices for description of uncertainty—B[a]P draft
‘Consideration-Decision-Justification’ in tabular form
LHP 3/24/2015
2015 SOT: Communication of Uncertainty in Hazard & Risk Assessment

10. Starting discussion questions…
Are these approaches useful and usable?
Improvements/Refinements?
Additional key aspects to consider?
Combined approaches?
Intended audiences?
Different approaches for different audiences?
How can we begin to define a path towards improved integration of uncertainty communication?
Either these approaches or others, yet undefined…
address a potential path forward re the integration of the approaches (still not addressed)
.… entertain discussion on the objectives and intended audience for the various proposals (or perhaps this could be entertained in the presentations).  While I understand that the objective was to inform the risk assessment community, the approaches range from simple (with less transparency) to more complex (with greater transparency).  Tiered structure with different degrees of sophistication, also an option but it would be extremely helpful in my view, to pose questions related to integration and/or refinement of the approaches.
LHP 3/24/2015
2015 SOT: Communication of Uncertainty in Hazard & Risk Assessment

11. 2015 SOT: Communication of Uncertainty in Hazard & Risk Assessment
Thank-you!
LHP 3/24/2015
2015 SOT: Communication of Uncertainty in Hazard & Risk Assessment