Felli JC, Hazen GB Sensitivity analysis and the expected value of perfect information. Med Decis Making. 1998 Jan-Mar;18(1):95-109. Erratum in: Med Decis Making. 2003 Jan-Feb;23(1):97.. Med Decis Making 2001 May-Jun;21(3):254.
Fenwick E, Claxton K, Sculpher M Representing uncertainty: the role of cost-effectiveness acceptability curves. Health Econ. 2001 Dec;10(8):779-87.
Ferrera PC, Bartfield JM Outcomes of anticoagulated trauma patients. Am J Emerg Med. 1999 Mar;17(2):154-6.
Fortuna GR, Mueller EW, James LE, Shutter LA, Butler KL The impact of preinjury antiplatelet and anticoagulant pharmacotherapy on outcomes in elderly patients with hemorrhagic brain injury. Surgery. 2008 Oct;144(4):598-603; discussion 603-5. doi: 10.1016/j.surg.2008.06.009. Epub 2008 Aug 29.
National Collaborating Centre for Acute Care (UK) Head Injury: Triage, Assessment, Investigation and Early Management of Head Injury in Infants, Children and Adults. London: National Collaborating Centre for Acute Care (UK); 2007 Sep.
Wilson JT, Pettigrew LE, Teasdale GM Structured interviews for the Glasgow Outcome Scale and the extended Glasgow Outcome Scale: guidelines for their use. J Neurotrauma. 1998 Aug;15(8):573-85.
The AHEAD Study: Monitoring Anticoagulated Patients Who Suffer Head Injury
Interventional studies are often prospective and are specifically tailored to evaluate direct impacts of treatment or preventive measures on disease.
Observational studies are often retrospective and are used to assess potential causation in exposure-outcome relationships and therefore influence preventive methods.
Expanded access is a means by which manufacturers make investigational new drugs available, under certain circumstances, to treat a patient(s) with a serious disease or condition who cannot participate in a controlled clinical trial.
Clinical trials are conducted in a series of steps, called phases - each phase is designed to answer a separate research question.
Phase 1: Researchers test a new drug or treatment in a small group of people for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
Phase 2: The drug or treatment is given to a larger group of people to see if it is effective and to further evaluate its safety.
Phase 3: The drug or treatment is given to large groups of people to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow the drug or treatment to be used safely.
Phase 4: Studies are done after the drug or treatment has been marketed to gather information on the drug's effect in various populations and any side effects associated with long-term use.
