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Articles 1 - 14 of 14

Full-Text Articles in Physical Sciences and Mathematics

Simulating Bipartite Networks To Reflect Uncertainty In Local Network Properties, Ravi Goyal, Joseph Blitzstein, Victor De Gruttola Dec 2013

Simulating Bipartite Networks To Reflect Uncertainty In Local Network Properties, Ravi Goyal, Joseph Blitzstein, Victor De Gruttola

Harvard University Biostatistics Working Paper Series

No abstract provided.


A General Instrumental Variable Framework For Regression Analysis With Outcome Missing Not At Random, Eric J. Tchetgen Tchetgen, Kathleen Wirth Nov 2013

A General Instrumental Variable Framework For Regression Analysis With Outcome Missing Not At Random, Eric J. Tchetgen Tchetgen, Kathleen Wirth

Harvard University Biostatistics Working Paper Series

No abstract provided.


Alternative Identification And Inference For The Effect Of Treatment On The Treated With An Instrumental Variable, Eric J. Tchetgen Tchetgen, Stijn Vansteelandt Nov 2013

Alternative Identification And Inference For The Effect Of Treatment On The Treated With An Instrumental Variable, Eric J. Tchetgen Tchetgen, Stijn Vansteelandt

Harvard University Biostatistics Working Paper Series

No abstract provided.


Identification And Estimation Of Survivor Average Causal Effects, Eric J. Tchetgen Tchetgen Nov 2013

Identification And Estimation Of Survivor Average Causal Effects, Eric J. Tchetgen Tchetgen

Harvard University Biostatistics Working Paper Series

No abstract provided.


On The Causal Interpretation Of Race In Regressions Adjusting For Confounding And Mediating Variables, Tyler J. Vanderweele, Whitney Robinson Nov 2013

On The Causal Interpretation Of Race In Regressions Adjusting For Confounding And Mediating Variables, Tyler J. Vanderweele, Whitney Robinson

Harvard University Biostatistics Working Paper Series

We consider different possible interpretations of the “effect of race” when regressions are run with race as an exposure variable, controlling also for various confounding and mediating variables. When adjustment is made for socioeconomic status early in a person's life, we discuss under what contexts the regression coefficients for race can be interpreted as corresponding to the extent to which a racial disparity would remain if various socioeconomic distributions early in life across racial groups could be equalized. When adjustment is also made for adult socioeconomic status, we note how the overall disparity can be decomposed into the portion that …


A Unification Of Mediation And Interaction, Tyler J. Vanderweele Nov 2013

A Unification Of Mediation And Interaction, Tyler J. Vanderweele

Harvard University Biostatistics Working Paper Series

We show that the overall effect of an exposure on an outcome, in the presence of a mediator with which the exposure may interact, can be decomposed into four components: (i) the effect of the exposure in the absence of the mediator, (ii) the interactive effect when the mediator is left to what is would be in the absence of exposure, (iii) a mediated interaction and (iv) a pure mediated effect. These four components respectively correspond to the portion of the effect that is due to neither mediation nor interaction, to just interaction (but not mediation), to both mediation and …


Attributing Effects To Interactions, Tyler J. Vanderweele, Eric J. Tchetgen Tchetgen Jul 2013

Attributing Effects To Interactions, Tyler J. Vanderweele, Eric J. Tchetgen Tchetgen

Harvard University Biostatistics Working Paper Series

A framework is presented which allows an investigator to estimate the portion of the effect of one exposure that is attributable to an interaction with a second exposure. We show that when the two exposures are independent, the total effect of one exposure can be decomposed into a conditional effect of that exposure and a component due to interaction. The decomposition applies on difference or ratio scales. We discuss how the components can be estimated using standard regression models, and how these components can be used to evaluate the proportion of the total effect of the primary exposure attributable to …


Sample Size Considerations In The Design Of Cluster Randomized Trials Of Combination Hiv Prevention, Rui Wang, Ravi Goyal, Quanhong Lei, M. Essex, Victor Degruttola Jul 2013

Sample Size Considerations In The Design Of Cluster Randomized Trials Of Combination Hiv Prevention, Rui Wang, Ravi Goyal, Quanhong Lei, M. Essex, Victor Degruttola

Harvard University Biostatistics Working Paper Series

No abstract provided.


Phylogenetic Linkage Among Hiv-Infected Village Residents In Botswana: Estimation Of Clustering Rates In The Presence Of Missing Data, Nicole Bohme Carnegie, Rui Wang, Vladimir Novitsky, Victor G. Degruttola Jun 2013

Phylogenetic Linkage Among Hiv-Infected Village Residents In Botswana: Estimation Of Clustering Rates In The Presence Of Missing Data, Nicole Bohme Carnegie, Rui Wang, Vladimir Novitsky, Victor G. Degruttola

Harvard University Biostatistics Working Paper Series

No abstract provided.


A Versatile Test For Equality Of Two Survival Functions Based On Weighted Differences Of Kaplan-Meier Curves, Hajime Uno, Lu Tian, Brian Claggett, L. J. Wei May 2013

A Versatile Test For Equality Of Two Survival Functions Based On Weighted Differences Of Kaplan-Meier Curves, Hajime Uno, Lu Tian, Brian Claggett, L. J. Wei

Harvard University Biostatistics Working Paper Series

With censored event time observations, the logrank test is the most popular tool for testing the equality of two underlying survival distributions. Although this test is asymptotically distribution-free, it may not be powerful when the proportional hazards assumption is violated. Various other novel testing procedures have been proposed, which generally are derived by assuming a class of specific alternative hypotheses with respect to the hazard functions. The test considered by Pepe and Fleming (1989) is based on a linear combination of weighted differences of two Kaplan-Meier curves over time and is a natural tool to assess the difference of two …


Más-O-Menos: A Simple Sign Averaging Method For Discrimination In Genomic Data Analysis, Sihai Dave Zhao, Giovanni Parmigiani, Curtis Huttenhower, Levi Waldron May 2013

Más-O-Menos: A Simple Sign Averaging Method For Discrimination In Genomic Data Analysis, Sihai Dave Zhao, Giovanni Parmigiani, Curtis Huttenhower, Levi Waldron

Harvard University Biostatistics Working Paper Series

No abstract provided.


Efficient Estimation Of Risk Ratios From Clustered Binary Data, Matthew Cefalu, Eric Tchetgen Tchetgen Mar 2013

Efficient Estimation Of Risk Ratios From Clustered Binary Data, Matthew Cefalu, Eric Tchetgen Tchetgen

Harvard University Biostatistics Working Paper Series

No abstract provided.


On The Restricted Mean Event Time In Survival Analysis, Lu Tian, Lihui Zhao, L. J. Wei Feb 2013

On The Restricted Mean Event Time In Survival Analysis, Lu Tian, Lihui Zhao, L. J. Wei

Harvard University Biostatistics Working Paper Series

No abstract provided.


A General Regression Framework For A Secondary Outcome In Case-Control Studies, Eric J. Tchetgen Tchetgen Jan 2013

A General Regression Framework For A Secondary Outcome In Case-Control Studies, Eric J. Tchetgen Tchetgen

Harvard University Biostatistics Working Paper Series

No abstract provided.