This is survey design question.
I'm desiging a form to help non-specialists identify species. I would like the user to be able to look at a species identifying features before deciding on ID. They could choose a species on the first screen, review the identifying features and at the end of that line of questioning a simple "Is it this species?" A "Yes" would add the species name to the form and done.
A "No" on the other hand would send them back to the start of the form and they could review another species until a positive ID is reached.
I suspect this is not possible given the linear nature of XLSForms and I might be thinking about it in the wrong way. I've reviewed some of the sample forms on the test aggregate server (e.g. the birds form) and some of the forms on the xlsform site. Nothing is fitting with my needs at the moment.
Given this project is looking at a very small number of species the other option is to put togther a very simple key (as in if species has these qualities go to this question etc until a positive ID is reached).
However keys are difficult to build for greater numbers of species.