Research Principles
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þ AHA, ERC, ILCOR 8 levels of evidence
 1. positive randomized clinical trial
 2. negative randomized clinical trial
 3. prospective nonrandomized trial
 4. retrospective nonrandomized trial
 5. case series
 6. animal studies (A/B)
 7. extrapolations
 8. rational conjecture and common sense

þ Placebo and Hawthorne Effects:
 - [Shoemaker WC.  Critical care research in the 1990s:  How our perceptions
   affect creativity.  Crit care Med 1994;22(6):1040-1043.]
 - [Turner JA,  Deyo RA,  Loeser JD,  Korff MV,  Fordyce WE:  The importance of
   placebo effects in pain treatment and research.  JAMA 1994; 271:1609-1614.]