Intended for healthcare professionals

Research Methods & Reporting Statistics Notes

Brackets (parentheses) in formulas

BMJ 2011; 343 doi: (Published 11 August 2011) Cite this as: BMJ 2011;343:d570

Brackets, pots and kettles

Bland and Altman 'correct' Huber-Wagner's version of the logit
transformation to ln[1/(p-1)]

Sorry but that should surely be (1-p) in there!

if p = 0.2 then p-1 = -0.8 and the result comes out as ln(-1.25)
which is not a real number.

Competing interests: No competing interests

12 August 2011
Phil McShane
University of Leeds