Many early studies on the relationship between smoking and l

Many early studies on the relationship between smoking and lung cancer in the 1950s found that smokers were about 13 times more likely to die from lung cancer than non-smokers. Still, people argued against a cause and effect conclusion, citing numerous possible confounding variables. Suppose a student argues that these studies are not convincing evidence because the researchers did not record the diet of the individuals. What more does the student need to say to provide a complete explanation of why diet is a potentially confounding variable?

Solution

A confounding variable is a variable which has an hidden effect on the outcome of a study. Now, diet does not have any hidden effect on smoking and lung cancer. Thus, diet is not a potentialy confounding variable.