MedLink Neurology Podcast is delighted to feature selected episodes from BrainWaves, courtesy of James E Siegler MD, its originator and host. BrainWaves is an academic audio podcast whose mission is to educate medical providers through clinical cases and topical reviews in neurology, medicine, and the humanities, and episodes originally aired from 2016 to 2021.   Originally released: October 11, 2018   As the name suggests, "evidence-based medicine" is dependent on published evidence to support our clinical practice and medical decision-making. Implicit in this is the notion that all published evidence reflects the truth that underlies the biology, pathophysiology, and pharmacology of our health.   This is not the case.   Clinical research and published findings can be extremely limited, and what you read in Lancet and NEJM should be interpreted with caution. In this week's episode of the "I wonder" series, where Jim Siegler speaks with Ali Hamedani on various topics in medicine and neurology, the speakers review the major biases inherent to the practice and interpretation of clinical research.   Produced by James E Siegler. Music by Jahzzar, Kai Engel, and Lee Rosevere. Sound effects by Mike Koenig, Daniel Simion. BrainWaves' podcasts and online content are intended for medical education only and should not be used for clinical decision-making.   REFERENCES   Anonymous. Randomised trial of intravenous streptokinase, oral aspirin, both, or neither among 17,187 cases of suspected acute myocardial infarction: ISIS-2. ISIS-2 (Second International Study of Infarct Survival) Collaborative Group. Lancet 1988;2(8607):349-60. PMID 2899772 Kazui H, Miyajima M, Mori E, Ishikawa M; SINPHONI-2 Investigators. Lumboperitoneal shunt surgery for idiopathic normal pressure hydrocephalus (SINPHONI-2): an open-label randomised trial. Lancet Neurol 2015;14(6):585-94. PMID 25934242 Montalban X, Hauser SL, Kappos L, et al. Ocrelizumab versus placebo in primary progressive multiple sclerosis. N Engl J Med 2017;376(3):209-20. PMID 28002688 Smith GC, Pell JP. Parachute use to prevent death and major trauma related to gravitational challenge: systematic review of randomised controlled trials. BMJ 2003;327(7429):1459-61. PMID 14684649   We believe that the principles expressed or implied in the podcast remain valid, but certain details may be superseded by evolving knowledge since the episode’s original release date.