Generic Software Tools for Model Checking and Display
Open systems, like R, allow the rapid dissemination of new methodology through user-contributed packages. There has been an explosion of these, however, the focus is typically on new models, methods of analysis, etc, rather than on generic tools that may enhance other aspects of the modelling process. Here, we consider from the point of view of both model checking and model display/interrogation.We illustrate the first with the hnp package for model checking using half-normal plots of diagnostic quantities, eg residuals. This package can be used with many common univariate response model objects and can easily be extended to any new class. We also consider the extension of these ideas to bivariate response models.Nomograms (graphical tools for complex expressions) have received renewed interest in recent years as a form of visualisation tool. The dynom package is an example of a Shiny app for model display using dynamic nomograms. We illustrate its use and discuss the general approach and its role as a communication and dissemination tool.