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Sponsoring Section/Society: ENAR

Session Slot: 10:30-12:20 Wednesday

Estimated Audience Size: 60-80

AudioVisual Request: Two Overheads

Session Title: Affecting Policy through Environmental Statistics

Session Organizer: Ryan, Louise M. Harvard University

Address: DFCI, 44 Binney Street, Boston Ma 02115

Phone: 617-632-3602

Fax: 617-632-2444


Session Timing: 110 minutes total (Sorry about format):

Chair - 5 minutes First Speaker - 25 minutes (including 3 minutes questions) Second Speaker - 25 minutes Third Speaker - 25 minutes Discussant - 15 minutes Floor Discusion - 15 minutes

Session Chair: Young, Linda J. University of Nebraska

Address: Department of Biometry U of Nebraska Lincoln NE 68583-0712

Phone: 402 472 2903

Fax: 402 483 2392


1. Dose-Rate Considerations in Risk Assessment: Statistical Models and Policy Implications

Williams, Paige L.,   Dept. of Biostatistics, Harvard School of Public Health

Address: Biostatistics, 677 Huntington Avenue Boston Ma 02115

Phone: (617) 432-3872

Fax: (617) 432-2832


Abstract: Regulatory agencies have become increasingly aware of the need to develop standards for a wider range of exposure conditions relevant for toxicity endpoints, particularly varying lengths of exposure. The strategy for comparing responses among exposures of different durations has often relied on a conjecture proposed by Haber (1924) that response levels should be equivalent for any constant multiple of dose times duration, i.e., whenever the cumulative exposure remains constant. More flexible statistical models have been developed for assessing joint effects of dose and duration, yet these typically require larger and more complex study designs. Current default approaches for setting regulatory standards in the context of dose-rate exposures will be reviewed, and implications of more flexible approaches on regulatory policy will be addressed.

2. Mechanistic Modeling in Environmental Policy: Challenges for Statistics

Portier, Christopher J.,   NIEHS

Address: NIEHS PO Box 12233 MD A3-06 Research Triangle Park, NC 27709

Phone: 919 541 4999

Fax: 919-541-1479


Abstract: There is now underway a concerted effort by the regulatory community to "improve" decisions about environmental health risks through the use of "mechanistic models" explaining the relationship between exposure and risk. The benefit from the use of these models is an increased linkage of a broad array of data sources and the u se of historical understanding of the etiology of a toxicity in the formulation of the model. However, these efforts result in a difficult task for statisticians i n terms of definition (what constitues "mechanistic modeling" as compared to an al ternative), parameter estimation (identifiability, likelihood construction, varian ce estimation, etc) and in validation of a highly complicated modeling scheme. Th is talk addresses some of these concerns and suggests avenues of research for stat isticians to improve the use of ``mechanistic models'' in risk assessment.

3. Regulating the Effects of Commercial Salmon Net Fisheries on Protected Seabirds

Conquest, Loveday L.,   Associate Dean And Professor, College Of Ocean & Fishery Sciences Univ. Of Washington

Address: Box 3355645 Seattle WA 98195-5645

Phone: 206 543 1708

Fax: 206 543 6263


Melvin, Edward F., University of Washington, Washington Sea Grant Program

Abstract: In developing regulations for fishing gear and fishing techniques that reduce the accidental entanglement of endangered seabirds, we compared entanglement rates and fish catch rates in different types of salmon fishnets, and across different times of day. We used loglinear models to analyze both bird entanglement and fish catch data. Results indicate that seabird entanglement and salmon catch rates vary significantly among fishnet types and times of day. Particular patterns of variation were specific to the type of bird being investigated. Common Murres and Rhinoceros Auklets responded differently (in terms of entanglement rates) to different types of nets, and depending upon the time of day. This can be problematic when trying to devise fishing regulations across a broad array of circumstances. Fishing policy changes based on our work involve use of visual net barriers, acoustic pingers for fishnets, and daytime only fishing to reduce endangered seabird bycatch by commercial salmon fishing boats.

Discussant: Ross, N. Phillip   Director for the Center for Environental Statistics, USEPA

Address: 401 M Street, SW Room 3101 Mail Stop 2163 Washington DC 20450

Phone: 202 260-5244

Fax: 202 260-8550


List of speakers who are nonmembers: None

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Next: biometric.soc.05 Up: Biometric Society (ENAR & Previous: biometric.soc.03
David Scott