hassediagrams:an R package that generates the Hasse diagram of the layout structure and the restricted layout structure

With the advent of modern statistical software, complex experimental designs are now routinely employed in many areas of research. Failing to correctly identify the structure of the experimental design can lead to incorrect model selection and misleading inferences. This paper describes the hassediagrams package in R that determines the structure of the design, summarised by the layout structure, and generates a Hasse diagram of the layout structure. By considering the randomisation performed, in conjunction with the layout structure, a set of randomisation objects can be defined that form the restricted layout structure. This structure can also be visualised using a generalisation of the Hasse diagram. Objects in the restricted layout structure can be used to identify the terms to include in the statistical model. The use of the procedure thus ensures consistency of model selection due to the systematic approach taken to generate the model.