PROXIMITIES Subcommand (PREFSCAL command)

The PROXIMITIES subcommand specifies the type of proximities that are used in the analysis. The term proximity is used for either similarity or dissimilarity data. Internally, PREFSCAL works with dissimilarities. Therefore, PREFSCAL converts similarities into dissimilarities by reflecting the data about its midpoint (depending on the conditionality chosen on the CONDITION subcommand), thus preserving the endpoints and the range.

DISSIMILARITIES. Dissimilarity data. This specification is the default when PROXIMITIES is not specified. Small dissimilarities correspond to small distances, and large dissimilarities correspond to large distances.

SIMILARITIES. Similarity data. Small similarities correspond to large distances, and large similarities correspond to small distances.

Example

PREFSCAL var01 TO var09
  /PROXIMITIES = SIMILARITIES.

• In this example, PREFSCAL expects the proximities to be similarities.