ABSTRACT
Clearly, BugsXLA can only offer a ˜nite number of analysis options. This chapter discusses how an experienced WinBUGS user can extend an analysis initially speci˜ed using BugsXLA. This might be to make inferences on additional quantities of interest, or extend the model to one not currently offered by BugsXLA. In order to do this, it is ˜rst necessary to be aware of the ˜les created by BugsXLA each time an analysis is speci˜ed. By default, these ˜les are deleted after importing the results back into Excel, but they can be saved by requesting that a bugfolio be created on the ‘MCMC Output & Options’ form; this is done by selecting the ‘Create Bugfolio’ check box (see Figure 2.7). Alternatively, BugsXLA can be made to create a bugfolio every time by changing the default setting on the ‘Options’ form (see Section 2.12), or if the decision to save all the ˜les is only made at the point when the results are being imported, the ‘Keep IO Dir (BugF#)’ check box can be selected on the ‘Import Results’ form (see Section 2.10). Whichever method is used, all the ˜les are saved in a sub-folder of the one in which the Excel workbook is stored. The name of this sub-folder is ‘BugF’ by default, or with integer suf˜x, but can be changed by the user if speci˜ed on the ‘MCMC Output & Options’ form. This sub-folder, the bugfolio, contains the following plain text ˜les that can be read using any standard text editor such as Microsoft’s Notepad:
BGX DataRect.txt
This contains the data being analyzed in the rectangular format readable by WinBUGS. Any factors will have had their levels converted into integers. It may also contain some indicator variables used to specify the model in WinBUGS.
