[kevao]

When there exists a disparity in these numbers, contributing factors are found. One of the primary candidates is SHS.

I'm with you on the normal distribution of deaths from lung cancer. But I still don't understand how they determine how many deaths were caused specifically by SHS as opposed to other environmental factors that could contribute to lung cancer.

[Hodar]

The investigation would be along the lines of: What did the people who did not smoke, but died from smoke-related illnesses have in common? Exposure to chlorine? Work in a bar? Spouse smoke? blah, blah, blah ... until a statistically significant number were found to have a link in common. The common link accepted by the AMA, and pretty much every medical, insurance and govermental agency in the world has been SHS.