The fortnightly BRAG meeting will be held this Thursday, September 5th, at 1 pm via Zoom/GP-Y801. This week we will have a presentation by Sithara Wijekoon along with a discussion.
Zoom link: https://qut.zoom.us/j/89593064596?pwd=qtCeeNwO6uarrZo8jxzo22pAx4WYWy.1
Meeting ID: 895 9306 4596 / Passcode: 403149
Sithara’s Talk
Title: Missing-data Imputation using Vine Copulas
Abstract: Dealing with missing data is a common challenge in observational studies, making data analysis and interpretation difficult. While traditional imputation methods including mean imputation, nearest neighbour donor imputation, regression imputation, and predictive mean matching are widely used for their simplicity, they often struggle to maintain the multivariate dependence structure, particularly in the presence of diverse marginal distributions and complex, nonlinear dependencies. To overcome these limitations, my project introduces new imputation methods based on vine copulas, specifically canonical vines (C-vines) and drawable vines (D-vines). These vines organise a cascade of bivariate copulas in the hierarchical tree structures to represent dependencies between variables, which allows accurate capture of complex relationships in high-dimensional datasets or datasets exhibiting diverse dependency patterns. The proposed methods employ modified algorithms for conditional sampling from C- or D-vines, allowing for the simulation of imputed values from the conditional distribution of missing variables given the observed variables.
See you there! 😊
Jamintha & Abi
BRAG Co-Chairs