FOCALCASES Subcommand (KNN command)
The FOCALCASES subcommand
allows you to mark cases of particular interest. For example, a researcher
wants to determine whether the test scores from one school district
– the focal case – are comparable to those from similar
school districts. He uses nearest neighbor analysis to find the school
districts that are most similar with respect to a given set of features.
Then he compares the test scores from the focal school district to
those from the nearest neighbors.
Focal cases could also be used in clinical studies to select control
cases that are similar to clinical cases. Focal cases are displayed
in the k nearest neighbors and
distances table, feature space chart, peers chart, and quadrant map.
Information on focal cases is saved to the files specified on the OUTFILE subcommand.
- Cases with a positive value on the specified variable are treated as focal cases. It is invalid to specify a variable with no positive values.
- There is no default variable list on the
FOCALCASESsubcommand.