help sqdes(SJ6-4: st0111)

Title

sqdes -- Describe sequence concentration

Syntax

sqdes
[if] [in]
[, options]

so apply same-order similarity

se apply same-elements similarity

graph display results graphically

gapinclude include sequences with gaps in the tabulation

subsequence(a,b) use only subsequence between positions a and b

Description

sqdes is a way to describe the concentration of sequences
in the dataset. Considering the limiting case when all respondents
share the same sequence, one would speak of a high concentration of
sequences, whereas one would speak of a low concentration if all
observed sequences were unique. Hence, the more only a few sequences are
shared by many respondents, the higher the concentration of sequences
is, whereas the more sequences that are unique, the lower the concentration.

The command sqdes provides this and some further
information about the concentration or diversification of sequences.

Options

so is used to request a frequency table, where similar
sequences have been grouped together beforehand. The concept for
similarity used with the option so is called same-order
similarity, because it treats sequences where the elements appear in
the same order. The sequence A-B-B-A would be treated identical to
A-B-A-A, because the elements A and B appear in the same order in both
sequences (first A, then B, and then A again).

se is used to request a frequency table, where similar
sequences have been grouped together beforehand. The concept for
similarity used with the option so is called same-elements
similarity, because it treats sequences that consist of the same
elements as identical. Hence, with this option the sequence B-A-A-B
would be treated as identical to A-B-B-A, because both sequences
consist of the elements A and B.

graph provides a simple vertical bar chart of the table
presented with sqdes. Sequences are highly concentrated if many
and/or high bars are on the right of the graph, and fairly unique if
they are on the left. You can specify all options available for
graph twoway bar to further control the look of the
graph.

gapinclude is used to include sequences with gaps in the
tabulation. The default behavior is to drop sequences with gaps from
the tabulation, because they cannot be used in the program sqom.
The term "gap" refers only to missing values on the element variable within
a sequence. Sequences with missing values at the beginning and at the end of a
sequence are included in any case. See sq for details.

subsequence(a,b) is used to include only the part of
the sequence that is between position a and b, whereby a and b refer
to the position defined in the order variable.

Author

Ulrich Kohler, University of Potsdam, ulrich.kohler@uni-potsdam.de

Examples

. sqdes

. sqdes, so

. sqdes, so graph

Also see

Online: sq, sqdemo, sqset,
sqdes, sqegen, sqstat, sqindexplot,
sqparcoord, sqom, sqclusterdat,
sqclustermat