Smoking ban advocates are pushing the study in Pueblo, Colorado showing a drop in heart attacks since a smoking ban was passed there in 2003.
Hold your horses.
According to AP Medical Writer Mike Stobbe, "(b)ut the study had limitations: It assumed declines in the amount of secondhand smoke in Pueblo buildings after the ban, but did not try to measure that. The researchers also did not sort out which heart attack patients were smokers and which were not, so it's unclear how much of the decline can be attributed to reduced secondhand smoke."
The study has only one legitimate conclusion - further study should be done to either validate the results with more thorough study - or invalidate the results with more thorough study.