user2016

Genetic evidence is often used as evidence in disputes. Mostly, the genetic evidence is DNA profiles and the disputes are often familial or crime cases. In this talk, we go through the statistical framework of evaluating genetic evidence by calculating an evidential weight. The focus will be the statistical aspects of how DNA material from the male Y chromosome can help resolve sexual assult cases. In particular, how an evidential weight of Y chromosomal DNA can be calculated using various statistical methods and how the methods use statistics and R. One of the methods is the discrete Laplace method which is a statistical model consisting of a mixture of discrete Laplace distributions (an exponential family). We demonstrate how inference for that method was initially done using R's built-in glm function with a new family function for the discrete Laplace distribution. We also explain how inference was speeded up by recognising the model as a weighted two-way layout with implicit model matrix and how this was implemented as a special case of iteratively reweighted least squares.