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