Mirror R/CRAN for internal use

The statistical analysis system R can be extended by a huge number of contributed packages which are stored in the central CRAN repository with multiple synced mirrors around the world. To access this repository from clients in a secure network, and install the packages in a local R installation may pose a security risk, require…

How to calculate (average) hazard ratios for parametric survival models based on the R/flexsurv package

This tutorial [PDF] aims to support the interpretation of parametric time-to-event models by explaining how to calculate the hazard ratio, which is a conventional effect size to evaluate clinical relevance of treatment effects. The following distributions, which are considered most important for health economic analyses, are implemented in the flexsurv package (cf ?flexsurvreg): exp: exponential…

Gradient Boosting Machines

Gradient Boosting Machines as a family of methods have been the “talk of the town” in the Machine learning world for a while now, with the specific flavour of Gradient Boosting Trees has been regarded as “the best off-the-shelf” classifier in the world” (Breiman, 1986/1987, see Hastie et al. 2013) [1].  A wonderful review about…

SAS launches free version for academics (SAS University Edition, SAS on Demand for academics)

Functionality seems limited, but interesting for learning SAS … Citing the SAS web page (not necessarily my  opinion): “The new SAS University Edition will offer free use of SAS foundational technologies, ideal for data and statistical analysis in teaching, research and self-paced learning. Available via quick download from the web, SAS University Edition will be…

Effective Genetic Risk Prediction Using Mixed Models

“To date, efforts to produce high-quality polygenic risk scores from genome-wide studies of common disease have focused on estimating and aggregating the effects of multiple SNPs. Here we propose a novel statistical approach for genetic risk prediction, based on random and mixed effects models. Our approach (termed GeRSI) circumvents the need to estimate the effect…

Workshop “Phenotype Prediction using Genomic Data” [ONLINE] – August 11th, 2014

“Many important traits in livestock, agriculture and human health have a quantitative genetic inheritance. Great advances have been achieved in genetics and statistics, which provided analytical methodologies (i.e. genome-wide prediction) that permit a better understanding and prediction of these complex traits. The objective of this workshop is to present and discuss recent results and theoretical…