Solve the problem.A researcher finds a positive correlation between the number of vaccinations and the incidence of autism. Can you conclude that vaccinations can cause autism? Suggest some ways that the researcher could go about establishing causality. Refer to the six guidelines for establishing causality.

Question

What will be an ideal response?

Answer 1

The researcher should not conclude that vaccinations cause autism without further research. Possible types of research are as follows:
1. Look for a correlation between vaccinations and autism among various groups - male, female, people of different incomes, ages, races, cultures, lifestyles. 
2. Find two groups which are alike in every respect except the number of vaccinations . Do those who have had more vaccinations have a higher incidence of autism? 
3. Look for evidence that the greater the number of vaccinations, the higher the incidence of autism.
4. Look for evidence that after other potential causes of autism have been accounted for, that the remaining cases occur among those who receive many vaccinations.
5. Conduct an experiment. Consideration should be given to whether this would be ethical. 
6. The researcher should try to determine the physical mechanism by which vaccinations could cause autism.