Posted by
Robert Edgell on
Nov 16, 2006; 4:37pm
URL: http://spssx-discussion.165.s1.nabble.com/Pearson-s-correlations-and-dichotomous-pairs-tp1072140p1072143.html
Stephen,
Many thanks for the clarification!
Best,
Robert
-----Original Message-----
From: Statisticsdoc [mailto:
[hidden email]]
Sent: Wednesday, November 15, 2006 5:14 PM
To: Robert;
[hidden email]
Subject: RE: Pearson's correlations and dichotomous pairs?
Stephen Brand
www.statisticsdoc.com
Robert,
The phi coefficient and Pearson's R are algebraically equivalent when you
are computing correlations between dichotomous variables. So, yes, SPSS
will give you phi, but not because it "switches" to a different formula, but
because the results are the same. Phi and many other formulae are
computationally simpler than Pearson's R but yield the same coefficient.
Pragmatically, you never need to worry about SPSS giving you something other
than the Phi coefficient when you are dealing with a pair of dichotomous
variables.
HTH,
Stephen Brand
For personalized and professional consultation in statistics and research
design, visit
www.statisticsdoc.com
-----Original Message-----
From: SPSSX(r) Discussion [mailto:
[hidden email]]On Behalf Of
Robert
Sent: Wednesday, November 15, 2006 5:39 PM
To:
[hidden email]
Subject: Pearson's correlations and dichotomous pairs?
It is my understanding that when Pearson's Correlation is used, SPSS (v13
and later) will calculate the exact correlation regardless of whether the
variables are continuous or dichotomous. So in case of a pair of
dichotomous variables, SPSS will "automatically" compute using phi . . .
can anyone confirm if this is true or not?
Many thanks,
Robert