title: Reduced falls in the elderly: tai chi or placebo or Hawthorne effect?
authors.forename: Alan R
authors.initials: AR
authors.lastname: Katz
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control* / Q000706:statistics & numerical data*; D000368:Aged; D006801:Humans; D016032:Randomized Controlled Trials as Topic / Q000379:methods*; D026302:Tai Ji / Q000379:methods*