@Doubtful,
What the hell does "digitized" mean, anyway? That's unclear to me. If you mean a different numeral was associated with the same question in the questionaires, you might just say that (which you go on to do).
I would suggest variations like:
(a) The questions (not questionaires) were not always presented in the same sequence
(b) ...the order of presentation was varied...
(c) the sequential presentation was not uniform.
There are, of course, many other ways of saying the same thing, but I don't think "digitized" is a good word choice here. Maybe that would mean something to most people, I don't know, but it doesn't mean much to me. I thought you must be referring to some computer processing, or something.