Bayesian designs with frequentist and Bayesian error rate considerations

So far, most Phase II trials have been designed and analysed under a frequentist framework. Under this framework, a trial is designed so that the overall Type I and Type II errors of the trial are controlled at some desired levels. Recently, a number of articles have advocated the use of Bavesian designs in practice. Under a Bayesian framework, a trial is designed so that the trial stops when the posterior probability of treatment is within certain prespecified thresholds. In this article, we argue that trials under a Bayesian framework can also be designed to control frequentist error rates. We introduce a Bayesian version of Simon's well-known two-stage design to achieve this goal. We also consider two other errors, which are called Bayesian errors in this article because of their similarities to posterior probabilities. We show that our method can also control these Bayesian-type errors. We compare our method with other recent Bayesian designs in a numerical study and discuss implications of different designs on error rates. An example of a clinical trial for patients with nasopharyngeal carcinoma is used to illustrate differences of the different designs.

Seabed Biodiversity on the Continental Shelf of the Great Barrier Reef World Heritage Area

The Great Barrier Reef is a unique World Heritage Area of national and international significance. As a multiple use Marine Park, activities such as fishing and tourism occur along with conservation goals. Managers need information on habitats and biodiversity distribution and risks to ensure these activities are conducted sustainably. However, while the coral reefs have been relatively well studied, less was known about the deeper seabed in the region. From 2003 to 2006, the GBR Seabed Biodiversity Project has mapped habitats and their associated biodiversity across the length and breadth of the Marine Park to provide information that will help managers with conservation planning and to assess whether fisheries are ecologically sustainable, as required by environmental protection legislation (e.g. EPBC Act 1999). Holistic information on the biodiversity of the seabed was acquired by visiting almost 1,500 sites, representing a full range of known environments, during 10 month-long voyages on two vessels and deploying several types of devices such as: towed video and digital cameras, baited remote underwater video stations (BRUVS), a digital echo-sounder, an epibenthic sled and a research trawl to collect samples for more detailed data about plants, invertebrates and fishes on the seabed. Data were collected and processed from >600 km of towed video and almost 100,000 photos, 1150 BRUVS videos, ~140 GB of digital echograms, and from sorting and identification of ~14,000 benthic samples, ~4,000 seabed fish samples, and ~1,200 sediment samples.

Portrait of Franz Matthiesen; London Portraits Men

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Portrait of Hans Bernkopf Portraits Men

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Studio portrait of Hans Bernkopf Portraits Men

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Studio portrait of Hans Bernkopf as a young man. Portraits Men

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Ellen Bernkopf nee Catzenstein pumping water outdoors; Ascona, Switzerland. Portraits Women

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Studio portrait of Ellen Bernkopf nee Catzenstein. Portraits Women

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Portrait of Ellen Bernkopf nee Catzenstein as an infant. Portraits Children

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Studio portrait of Ellen Bernkopf nee Catzenstein; Ascone, Switzerland. Portraits Women

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Outdoor portrait of Ellen Bernkopf nee Catzenstein with her husband Hans Bernkopf; Paris, France. Portraits Couples

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Profile view of bust of Henriette Gottschalk nee Rothschild by Ellen Bernkopf (Colmar) nee Catzenstein.

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Portrait of Franz Catzenstein with his uncle Ernst Gottschalk.

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Ernst Gottschalk and his mother Henriette Gottschalk nee Rothschild with sheitl.

Photograph owned by Yael Arnold, Waldstetten; copied by Thomas Krakauer

Portrait of Franz Catzenstein and his little sister Ellen. Portraits Children

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