Which is the easier question to answer?:
“Tell me about France” or,
“Tell me about the restaurants in the village of Venosc that serve Italian food” ?
It’s very obviously the latter (assuming you have the information available in the first place). It’s the difference between these two questions that explains how some reports can be a single page (and useful) or 150 pages and still miss the point.
I’ve sat through many report design sessions where the people building the report spend lots of time guessing what the user of the report will want to know. If you find yourself in this situation alarm bells should start ringing in your ears.
At this point you need to cheat. You need to ask the report customer “What question(s) are you trying to answer?”. That will usually clear things up. If they don’t know what question they are trying to answer then you have some more work to do.