by Usha Govindarajulu | Aug 16, 2023 | Biostatistics, Blog, COVID-19, Epidemiology, Healtcare, Usha Govindarajulu

The authors developed a proportional incidence model to estimate vaccine effectiveness (VE) but at the population level. Understanding VE during the COVID-19 pandemic was very important. Since obtaining individual level data linkages, the authors used aggregated...
by Usha Govindarajulu | Aug 2, 2023 | Biostatistics, Blog, Usha Govindarajulu

August 2, 2023 In this article published in June online, Lancker et al describe a way for valid inference of hazard ratios from a Cox regression after variable selection. The problem has been that it is unknown which amount of covariates to use to control for...
by Usha Govindarajulu | Jul 19, 2023 | Biostatistics, Usha Govindarajulu

Statistical issues in survival analysis (Part XI) July 19, 2023 The authors, Ning et al, have proposed what they refer to as a “broad class” of “so called” Cox-Aalen transformation models which have elements of both multiplicative and additive covariate effects...
by Usha Govindarajulu | Jul 6, 2023 | Biostatistics, Blog, Usha Govindarajulu

July 5, 2023 The restricted mean survival time (RMST) is a concept that has been invented in survival analysis as an alternative to the hazards ratio, which can be difficult to interpret and also, as derived from Cox model, can have difficulty fitting into the...
by Usha Govindarajulu | Jun 23, 2023 | Blog, Usha Govindarajulu

June 21, 2023 Quantile regression has been around for awhile but has not been used so extensivly in survival analysis, namely for comparisons at the population level. The authors, Williamson et al, proposed analyzing relative survival data using quantile regression...
by Usha Govindarajulu | Jun 9, 2023 | Biostatistics, Blog, Machine Learning, Usha Govindarajulu

June 7, 2023 The authors reviewed methods for complex survival data in terms of frailty models, like the recent advances and R packages. They explored areas of clustered outcomes, competing risks, illness-death model. They did admit their review did not cover two...