Intended for healthcare professionals

Letters Measuring clinical difference

Guidance on minimally important clinical difference and trial size is needed

BMJ 2011; 343 doi: (Published 25 July 2011) Cite this as: BMJ 2011;343:d4375
  1. Jonathan A Cook, methodologist1,
  2. Craig R Ramsay, programme director1,
  3. Luke D Vale, professor of health economics2
  4. On behalf of the DELTA project group
  1. 1Health Services Research Unit, University of Aberdeen, Aberdeen AB25 2ZD, UK
  2. 2Institute for Health and Society, Newcastle University, Newcastle upon Tyne NE2 4AX, UK
  1. j.a.cook{at}

The authors of a randomised controlled trial that compared surgical intervention with rehabilitation in patients with chronic low back pain reported a statistically significant difference of less than 10 points in the Oswestry disability index between groups.1 They concluded that it “did not clearly exceed the pre-specified minimally important …

View Full Text

Log in

Log in through your institution


* For online subscription