```help sqdes                                                      (SJ6-4: st0111)
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Title

sqdes -- Describe sequence concentration

Syntax

sqdes [if] [in] [, options]

options               Description
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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
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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, WZB, kohler@wz-berlin.de

Examples

. sqdes

. sqdes, so

. sqdes, so graph

Also see

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