I'm in a situation where there is no accounts. There is only offer-centers (which need quality ratings) and offer-takers. Every time an offer is taken a transaction is taken there is evidence of it, ...
There are a number of ways to assign severity ratings of usability problems (For an overview see this post by Jeff Sauro). Jakob Nielsen's four-step scale often seems to be the standard in Heuristic ...
Rating scales are used on many websites, generally as a numerical value (e.g. 1-5) or a qualitative value (e.g. very good - very bad). For input it is easy to contain the values to whole values so ...