Epidemiological studies questions

Which of these are features of a good study?
The study has a large sample size
The study collects a lot of data and it is then analysed to look for correlations
The study takes place over a long time
The study is done quickly so that the results are discovered as soon as possible
The study compares two groups of carefully matched people
The study looks at a small number of people who are closely matched
The study has been checked by people who know about the thing being studied
The study has been supported by evidence from other studies

iDevice icon Case Study
Using the example of the MMR vaccine, suggest three reasons why it may not be right to force people to follow health programmes developed through the use of epidemiological studies.