Solve the problem.A researcher suspects that pesticides in foods cause cancer. Suggest some ways that she could go about establishing causality. Refer to the six guidelines for establishing causality. For each guideline suggest some research that should be pursued. Discuss any challenges that the researcher would face in establishing causality.

Question

What will be an ideal response?

Answer 1

1. Look for a correlation between pesticides and cancer rates among various groups - women, men, people of different ages, races, cultures, lifestyles. 
2. Find two groups which are alike in every respect except the level of pesticides in their diet. The researcher should compare the incidence of cancer for the two groups. Is the incidence of cancer higher for those with higher levels of pesticides in their diet? Such groups may be difficult to find - people who voluntarily choose to eat organic food may also make other healthy life style choices. 
3. Look for evidence that the higher the level of pesticides in a person's diet, the greater the risk of cancer.
4. Look for evidence that after other potential causes of cancer have been accounted for, that the remaining cases occur among those exposed to pesticides in their diet.
5. In this case an experiment would be unethical since the researcher suspects that pesticides cause cancer.
6. The researcher should try to determine the physical mechanism by which pesticides could cause cancer.