10 Questions for David Seymour: #5

by Care Alliance, 18 July 2017

Click here to view the 10 Questions For David Seymour website, with questions (and answers!) being added between 12 July and 25 July.

#5 What is the error rate of medical diagnosis?

  • The diagnosis is wrong 10–15% of the time.” A diverse range of research into this issue over the past several decades suggests that this range is very much on target (p.1).
  • Winters, Bradford et al (2012, p. 894) note, in a paper published in the British Medical Journal, that 28% of autopsies report at least one misdiagnosis. An autopsy-confirmed study of 500 cases between 1959 and 1999/2000 (2012, p. 159) showed that in spite of the progress in diagnostic technology, the rate of false-positive diagnoses (people falsely diagnosed as having a particular condition) increased between 1959 and 1999/2000 from 7% to 15%.
  • A study of doctors’ prognoses (the medical prediction of the course of a disease over time) for terminally Ill patients found that only 20% of predictions were accurate – that is, within 33% of actual survival time.
  • To qualify for assisted suicide under Oregon’s “Death With Dignity Act” a doctor needs to determine that a person will die within six months, the same provision found in David Seymour’s Bill. In Oregon, the range of days between request and death over the period 1998-2015 is 14 to 1009 days (p.11). This means that at least one person judged eligible for assisted suicide on the basis they would die within six months survived for 2 years and 9 months.


Conclusion: Medical diagnosis is widely accepted as being wrong in at least 10-15% of cases and medical prognoses are inaccurate up to 80% of the time. Under the Bill that David Seymour has drafted, significant numbers of patients could decide to end their lives in error because of a misdiagnosis, and doctors would be asked to make claims about a patient’s prognosis which they cannot possibly substantiate with a high degree of accuracy.