title: Statistician expert witnesses in agreement on relative hazards.
abstract: 'If anticoagulants had been administered sooner, my client would not have died' was a central claim put to us, as statistician expert witnesses, by a Claimant's and Defendant's lawyers. To assist other litigants, and without identifying the specific case, we set out the study types that contribute to the evidence base, and their limitations. We then explain why it is difficult to adduce evidence about the relative risk of dying from pulmonary embolism within 12 hours of admission to accident and emergency even when it is well accepted that anticoagulation reduces the risk of dying within the next seven days of patients at objectively confirmed risk of pulmonary embolism. No matter how much we may want an answer, or how tragic an individual outcome, we can only work from the available evidence or work to improve the evidence base, which needs to be resourced.
authors.forename: Sheila M
authors.initials: SM
authors.lastname: Bird
authors.forename: Jane L
authors.initials: JL
authors.lastname: Hutton