Dear Allstat,
I've come across a paper where the correlation coefficient of final
measurement (Y) with percentage change from baseline (X), ie: ((Y-X)/X), was
calculated.
It's well known that change from baseline (Y-X) is correlated with both
final and baseline, even when Y and X are uncorrelated (+0.7071, and
-0.7071, respectively).
What correlation is to be expected between Y and (Y-X)/X, when Y and X are
uncorrelated?
Regards,
Sean McGuigan
Boehringer Ingelheim
Ellesfield Avenue
Bracknell
Berkshire RG12 8YS
phone: 01344 74 6766
fax: 01344 74 6906
email: [log in to unmask]
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