R help - Jan 2006 - Clustering Question

Hi group,

My case has N physicians with each seeing M patients. 
One physician could have seen a group of patients, or,
a patient could have been seen by multiple number of
physicians.  In order words, there are overlaps.  Now,
I have the following NxM matrix

              Patient#1 Patient#2 Patient#3 .......
Patient#m
Physician#1       1        0          1     .......   
 0
Physician#2       1        1          1     .......   
 1
Physician#3       0        1          0     .......   
 1
.                 .        .          .     .......   
 .       
.                 .        .          .     .......   
 .       
Physician#n       1        1          0     .......   
 0

"1" indicates previous encouter and "0" otherwise.  My
aim is to identify physician group practice based on
the common patients they see.  Any suggestion on which
R package would best serve this purpose?  Thank you so
much!

Regards,
Kelvin

For the dissimilarity metric I would suggest manhattan, as provided by dist
(base package), daisy, agnes (both cluster package), for in your case a common
"0" is meaningful - means that both pysicians didn't see the
patient.

 

When using complete linkage you can see exactly how many patients (seen or not
seen) the pysicians in one cluster have at least in common. If the height goes
up too fast so that you would have to extract to many clusters you can use
average linkage.

 

For the clustering you can use hclust from the base package, agnes from the
cluster package, or, when hclust or agnes run out of memory, clara (see thread 
[R] cluster analysis for 80000 observations)

 

sincerely, Markus

___________________

Markus Preisetanz

Consultant

 

Client Vela GmbH

Albert-Roßhaupter-Str. 32

81369 München

fon:          +49 (0) 89 742 17-113

fax:          +49 (0) 89 742 17-150

mailto:markus.preisetanz@clientvela.com
<mailto:markus.preisetanz@clientvela.com>



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