Why do so many posters here not finally catch on to what the word correlation involves? I've tried my best to post about some good charts in detail, and talk about what correlation entails and doesn't entail for some time now, and yet the "My so and so is so and so and therefore no correlation can exist" or the "I knew someone that doesn't fit correlation and therefore the correlation can't exist" posts abound like wildfire around here. One would think that ignorance has to give way some time. Unless it's just some hard headed PCness going on, but even then that's no excuse for giving a singular or few examples as proof a correlation is impossible. It doesn't work that way. Here: Just because someone smokes and never develops lung cancer doesn't mean there isn't an overall correlation. Charts indicate there is. correlation: Definition, Synonyms and Much More from Answers.com Statistics. The simultaneous change in value of two numerically valued random variables: the positive correlation between cigarette smoking and the incidence of lung cancer; the negative correlation between age and normal vision.