Re: Patient reported outcome measures: how are we feeling today?
An example of regression to the mean?
John Appleby's figure, a plot of preoperative score against "Health gain" (postoperative score-preoperative score) shows a tendency for better preoperative health to be associated with smaller health gains. Isn't this an example of regression to the mean [1] and so wouldn't a more preferable way of depicting any association be via a plot of postoperative score against the mean of both the preoperative and postoperative scores?
Perhaps Bland or Altman could comment!
[1] Bland JM, Altman DG. (1994) Some examples of regression towards the mean. 309, 780.
[2] Bland JM, Altman DG. (1986).Comparing methods of measurement: why plotting difference against standard method is misleading. Lancet, 346, 1085-7.
Rapid Response:
Re: Patient reported outcome measures: how are we feeling today?
An example of regression to the mean?
John Appleby's figure, a plot of preoperative score against "Health gain" (postoperative score-preoperative score) shows a tendency for better preoperative health to be associated with smaller health gains. Isn't this an example of regression to the mean [1] and so wouldn't a more preferable way of depicting any association be via a plot of postoperative score against the mean of both the preoperative and postoperative scores?
Perhaps Bland or Altman could comment!
[1] Bland JM, Altman DG. (1994) Some examples of regression towards the mean. 309, 780.
[2] Bland JM, Altman DG. (1986).Comparing methods of measurement: why plotting difference against standard method is misleading. Lancet, 346, 1085-7.
Competing interests: No competing interests