One of the most common mistakes I find when editing is the misuse of the adjective “relative” or its derivative adverb “relatively.” Here’s an example:
She was a relatively heavyset woman.
What is the woman’s appearance relative to? Twiggy? A hippopotamus?
When describing an entity as relative, it needs to be compared to something else. The New Oxford American Dictionary, 2nd edition (on my iBook) defines relative as
considered in relation or in proportion to something else: existing or possessing a specified characteristic only in comparison to something else; not absolute
Unless you clarify what is being compared, “relative” and “relatively” add no meaning to your writing and should not be used (unless, of course, you’re talking about your Uncle Frank from Oakland).
Many writers are afraid of being forceful, lest their readers disagree with them. So they dilute their conclusions with meaningless adjectives and adverbs.
If you’re afraid of your conclusions being misinterpreted, use specific words that clarify your opinion. If you’re just afraid your audience won’t like what you have to say, don’t be. An irritated reader often denotes an effective author.