[lockjaw02]

"The incidence(s) of cancer(s) associated with smoking are easy to figure. Find out how many people have a certain cancer. Then figure how many of those people with the cancer smoked or did not smoke. If the incidence of cancer(s) is statistically significantly higher in the smoking population, then you have a link.

It's not that simple. If it were, then why are so many epidimiologists and other researchers still getting grant money to continue research to try to figure it out?

[realpatriot71]

All I was pointng out is how one draws a statistical link between smoking and cancer(s). The how and why, yeah, that gets the research money.

For instance if you have a similar (as many things being equal as possible) group of 100, say bladder cancer patients, and you notice that 60 or 70 of these patient report either currently smoking or past smoking, you have a statistical link. How chemicals in cigaretes directly cause the cancer would be for the researchers. Although, the general eitiologies of cancer(s) are pretty well understood at this time.