From reading previous questions about modal windows, my understanding is that they're best used for short required processes, or for providing help/info during a process that shouldn't be interrupted by going to a new page.
My current project is an online education site. The content expert wants to use modal windows for some formative activities, because they believe it will help the user stay focused on the task while they're doing it. These are not assessments, so there is no need to prevent users from looking up other content while they work.
I'm working with restrictions on the size of the modal window which mean that the activities get kind of crammed in. My preference would be to give each activity it's own page - I think it will allow the content to 'breathe' while still removing distractions.
I can't seem to find any user-testing results for anything similar. Has anyone faced a similar situation and had a clear result or user preference?