Types of Study

Some sample answers describing the "ideal" studies for each question:

Diagnosis	A representative sample of patients are given the test; the results are compared with a definitive "gold standard" of diagnosis to see if they have the target disorder.	Cohort study
Harm or Causation	A representative sample of patients receive either exposure to the potentially harmful or causative agent or to a control, then compared to see if they develop the outcome of interest.	Randomised Controlled Trial or Case Control study
Prognosis	A representative sample of patients who have the prognostic factor of interest are followed forwards in time to see if they develop the outcome of interest.	Cohort study
Treatment or Prevention	A representative sample of patients are assigned to receive either the treatment or a control intervention, then compared to see if they develop the outcome of interest	Randomised Controlled Trial
Experience or Meaning	A representative sample of patients are canvassed to identify their experiences, attitudes and behaviours.	Qualitative study