SPSS® 12.0 Command Syntax Reference

236 CLUSTER
BSHAPE[(p[,np])] Binary shape difference. This dissimilarity measure has no upper or
lower limit.
DISPER[(p[,np])] Dispersion similarity measure. The range is −1 to +1.
VARIANCE[(p[,np])] Variance dissimilarity measure. This measure has a minimum value
of 0 and no upper limit.
BLWMN[(p[,np])] Binary Lance-and-Williams nonmetric dissimilarity measure. This
measure is also known as the Bray-Curtis nonmetric coefficient. The
range is 0 to 1.
METHOD Subcommand
PATTERN( x, y)
BSHAPE( x, y)
DISPER( x, y)
VARIANCE( x, y)
BLWMN( x, y)
METHOD specifies one or more clustering methods.
• If the METHOD subcommand is omitted or included without specifications, the method of
average linkage between groups is used.
• Only one METHOD subcommand can be used, but more than one method can be specified
on it.
• When the number of items is large, CENTROID and MEDIAN require significantly more
CPU time than other methods.
BAVERAGE Average linkage between groups (UPGMA). BAVERAGE is the default and
can also be requested with keyword DEFAULT.
WAVERAGE Average linkage within groups.
bc
( a+ b+ c + d)
2
= -------------------------------------
SINGLE Single linkage or nearest neighbor.
COMPLETE Complete linkage or furthest neighbor.
( a+ b+ c + d)
( b+ c)
( b– c)
2 –
( a + b + c + d)
2
= -----------------------------------------------------------------------------
ad – bc
( a+ b+ c+ d)
2
= -------------------------------------
b + c
= --------------------------------------
4( a+ b+ c+ d)
b+ c
=
-----------------------
2a + b + c
CENTROID Centroid clustering (UPGMC). Squared Euclidean distances are commonly
used with this method.