A friend of mine is an analyst for an investment bank. In normal circumstances he’d feed a company’s data into his excel spreadsheets and, because his spreadsheets are much more clever than mine, they tell him whether to make a buy, hold or sell call on a particular stock.
Of course ‘normal’ circumstances are hard to come by, so my friend usually has to combine what his spreadsheets tell him with a bit of good old-fashioned market savvy to come up with the answer.