PMCH Faculty Candidate Seminar

May 24, 2011

"Combining stratified and unstratified log-rank tests in paired survival data"

 

Presented by PMCH Faculty Canidate

Changyong Feng, PhD
Assistant Professor
Department of Biostatistics and Computational Biology
University of Rochester Medical Center
http://www.urmc.rochester.edu/biostat/people/faculty/feng.cfm

 Wednesday, June 1
12:00 - 1:00 pm
1.104 Ewing Hall

Abstract: The log-rank test is the most widely used nonparametric method for testing treatment differences in survival between two treatment groups due to its efficiency under the proportional hazards model. Most previous work on the log-rank test has assumed that the samples from the two treatment groups are independent. This assumption is not always true. In multi-center clinical trials, survival times of patients in the same medical center may be correlated due to factors specific to each center. For such data we can construct both stratified and unstratified log-rank tests. These two tests turn out to have very different powers for correlated samples. An appropriate linear combination of these two tests may give a more powerful test than either individual test. Under a bivariate frailty model, we obtain closed form asymptotic local alternative distributions and the correlation coefficient between these two tests. Based on these results we construct an optimal linear combination of the two test statistics to maximize the local power. Simulation studies with Hougaard's model confirm our construction. We also study the robustness of the combined test by simulations.

***Pizza Provided***

Congratulations to the 20th Annual Forum on Aging Poster Session winners!!

Student Poster Award Winners
Neuroscience – Kara Barber & Claudia Marino
Basic Science – Danelo Cortez
Rehabilitation – Kay Kulkarni
Health Disparities – Jaqueline Contrera Avila & Mary Margaret King
Medical Effectiveness – Keli Perino
Clinical Trials & Implementation – Leyla Akhverdiyeva

Congratulations to the 20th Annual Forum on Aging Poster Session winners!!

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To view all the photos from the event, click here: http://scoa.dphoto.com/#/album/7c9ecw

Congratulations Naiomi Jamal!!

Jamal, Naiomi

Please join me in congratulating Naiomi Jamal on her 2016 President's Cabinet Award! She received this for her program focused on Parent Based Teen Pregnancy Prevention. This is a very prestigious award - Congratulations Naiomi!

Congratulations LJ Panas on your new job at Kansas Health Institute!!

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Lawrence John Panas, Ph.D., Senior Analyst, joined KHI in 2016 after earning a doctorate degree in population health sciences and a master's degree in public Health from UTMB. His work at UTMB focused on community health improvement and also on public health systems and services. Prior to joining KHI, he was a graduate/research assistant at the UTMB. During that time, Lawrence was also involved in a wide range of work related to issues such as aging, disability, mortality, minority health and health disparities.

Congratulations to Zakkoyya Lewis on your new job at Beachbody, LLC.

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Zakkoyya (Koyya) Lewis accepted a position at Beachbody, LLC as their Fitness Research Manager in their Fitness and Nutrition Results department. This position is the first of its kind. As the Fitness Research Manager, Koyya is responsible for standardizing the measurement protocols for test groups on new products sponsored by Beachbody. She is responsible for the collection and evaluation of all test group data. It is also her responsibility to ensure that claims on new fitness programs meet scientific standards. In addition to running test groups, Koyya works directly with UTMB alum Erin Glynn, PhD and Research & Development as well as Digital Productions. She works as a liaison between departments to identify ways to improve programs and motivate customers.  

Congratulations Dr. Arcari and Dr. Rudkin!! 

Christine M. Arcari, PhD, MPH

Rudkin, Laura

Please join me in congratulating SOM Year 2 student Lynda Chowdhury and Drs. Arcari and Rudkin on their 2016 President's Cabinet Award! They received this for their application titled Health Fair Kits To Go: Turning Service into Service Learning. This is another very prestigious award for our department - Congratulations Lynda, Dr. Arcari, and Dr. Rudkin!

Please join us in wishing Joseph Saenz, PhD a farewell as he embarks on a new adventure.

 

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 Joseph Saenz obtained his PhD and is going to be a Post-Doctoral Fellow at the University of Southern California, Davis School of Gerontology, working with Dr. Eileen Crimmins and colleagues.

During his PhD stay at UTMB Department of Preventive Medicine and Community Health, and SCOA, he published several papers on aging among U.S. Hispanics and Mexicans. He consistently made presentations in local, national, and international professional meetings and conferences, winning several honors and awards.

At SCOA, he also coordinated the MHAS research work group.

We will miss him for his great scholarship, extraordinary citizenship, and personal disposition!

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