MDS and Cluster Analysis Examples

Michael Friendly
Psychology 6140

SAS Sample Library

The programs below are distributed with SAS (Ver 6.08 and later) and are stored in the directory !sasroot\stat\samples.
mdsauto sas
Similarities of automobiles with confidence ratings. 10 Subjects rated the similarity of pairs of 20 automobiles, and gave confidence judments in their ratings. An initial unweighted analysis is followed by one in which the confidence judgments are used as weights in the MDS analysis.
mdscity sas
Intercity flying distances: Ordinal, interval & ratio MDS analysis with good and bad starting configurations.
mdscola sas
Cola experiment: 46 subjects, 6 cola drinks rated for similarity in taste and smell. Ordinal & interval replicated MDS analysis.
mdsdist sas
Computing a distance matrix for 0/1 data.
mdsex sas
Examples from the User's Guide. Includes Jacobowitz body parts data for 6 yr olds and adults: Nonmetric weiughted INDSCAL analysis.
mdsindsp sas
MDS plots of group & individual configuration spaces. Using the data on judged similarity of programming languages, an INDSCAL model is fit, then the individual subjects' configurations are plotted.
mdslang sas
Similarity of 14 common programming languages rated by 10 graduate students: INDSCAL analysis plus one MDS analysis for each subject.
mdsperc sas
Intercity distance perception: Judged distances among 10 American cities. Asymmetric data, INDSCAL analysis.
mdsrank sas
Ranked flying distances: Data from MDSCITY converted to ranks, ordinal, interval & ratio MDS analyses with good and bad starting configurations.
mdssoda sas
Taste and smell soda experiment. Dissimilarity judgments from 46 subjects about 6 sodas, ordinal measurement level
mdsuni sas
Perfect unidimensional row-conditional data, with missing rows, interval and ordinal analysis. Replicated asymmetric analysis.
distance sas
A general macro for computing many different types of distance/similarity measures.
clustex1 sas
Intercity flying distances analyzed by a variety of methods available in Proc CLUSTER.
clustex2 sas
Birth and death rates in countries in 1976 analyzed by a variety of methods available in Proc CLUSTER.
clustex3 sas
Fisher's Iris data, Proc CLUSTER and canonical discriminant analysis.

PSYCH614 Disk

The programs below are stored in the Psych614 directory, N:\sasuser\psy6140\examples\cluster.
Averaged judged similarity of 12 countries.
INDSCAL analysis of Helm's data on color perception in normal and color-blind subjects.
Rates of intermarriage among 8 ethnic groups in Hawaii were used by Parkman & Sawyer (1967) to define distances among these groups which were studied by MDS techniques. This analysis uses an INDSCAL model to examine changes over time and compares the results with PROC CLUSTER.
Shows use of Proc CANCORR to fit the Vector Model and Ideal Point Model to relate ratings of automobiles on various properties to the MDS space.
Mutation distances among 20 species (Fitch & Margoliash data): MDS compared to CLUSTER procedure. The mutation distances were used by Fitch & Margoliash to derive a phylogenetic tree.
Constructing a similarity rating form with SAS. For the experiment on similarities among programming languages in
Distance estimates of 25 natural concepts rated by psychology undergraduates and biology graduate students (Schvanaveldt data): The items were chosen to have both hierarchical and non-hierarchical relationships, rather than underlying continuous dimensions.