Apple Inc. (NASDAQ: AAPL ) CEO Tim Cook has offered some sage advice to analysts: even if a supply chain rumor is accurate, it's impossible to interpret accurately what it means for the overall business. This hasn't stopped analysts from trying, however. In a survey of Apple Inc. (NASDAQ:AAPL) supply chain rumors going back more than a year, I found that they were a very poor predictor of financial performance for any given Apple Inc. (NASDAQ:AAPL) product or for Apple Inc. (NASDAQ:AAPL) as a whole. However, I did find that the rumors correlated well with subsequent new product introductions.