I realise this is one of those "Don't start from here" type questions, and I did indeed tell them not to "start from here" but it would be a shame to junk the data.
Basically I have some interval normal data, Likert scale type stuff, from two groups, at time one and time two, and I know that some subjects in time two are the same ones as from time one, so really the data should be paired. However, the data was collected anonymously so we just have two groups to compare.
My best thought would be that I could report a very conservative estimate of difference and then say "for all the problems with data collection, this is the smallest the effect is likely to be".
If significance is possible too, i.e. "and I am reasonably confident this effect is nonzero" then, great.
I don't even know where to begin looking up such a stupid way of analysing data. Would bootstrap be useful at all?
Any suggestions gratefully received, as I say highly conservative ones I think would be fine.