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SPSS® 12.0 Command Syntax Reference

SPSS® 12.0 Command Syntax Reference

SPSS® 12.0 Command Syntax Reference

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104 ALSCAL<br />

ASYMMETRIC Asymmetric data matrix or matrices. The corresponding values in the<br />

upper and lower triangles are not all equal. The diagonal is ignored.<br />

RECTANGULAR Rectangular data matrix or matrices. The rows and columns represent<br />

different sets of items.<br />

Example<br />

ALSCAL VAR=V1 TO V8 /SHAPE=RECTANGULAR.<br />

• ALSCAL performs a classical MDU analysis, treating the rows and columns as separate<br />

sets of items.<br />

LEVEL Subcommand<br />

LEVEL identifies the level of measurement for the values in the data matrix or matrices. You<br />

can specify one of the keywords defined below.<br />

ORDINAL Ordinal-level data. This specification is the default. It treats the data as ordinal,<br />

using Kruskal’s (1964) least-squares monotonic transformation. The analysis is<br />

nonmetric. By default, the data are treated as discrete dissimilarities. Ties in the<br />

data remain tied throughout the analysis. To change the default, specify UNTIE<br />

and/or SIMILAR in parentheses. UNTIE treats the data as continuous and resolves<br />

ties in an optimal fashion; SIMILAR treats the data as similarities. UNTIE and<br />

SIMILAR cannot be used with the other levels of measurement.<br />

INTERVAL(n) Interval-level data. This specification produces a metric analysis of the data<br />

using classical regression techniques. You can specify any integer from 1 to<br />

4 in parentheses for the degree of polynomial transformation to be fit to the<br />

data. The default is 1.<br />

RATIO(n) Ratio-level data. This specification produces a metric analysis. You can<br />

specify an integer from 1 to 4 in parentheses for the degree of polynomial<br />

transformation. The default is 1.<br />

NOMINAL Nominal-level data. This specification treats the data as nominal by using a<br />

least-squares categorical transformation (Takane et al., 1977). This option<br />

produces a nonmetric analysis of nominal data. It is useful when there are<br />

few observed categories, when there are many observations in each category,<br />

and when the order of the categories is not known.<br />

Example<br />

ALSCAL VAR=ATLANTA TO TAMPA /LEVEL=INTERVAL(2).<br />

• This example identifies the distances between U.S. cities as interval-level data. The 2 in<br />

parentheses indicates a polynomial transformation with linear and quadratic terms.

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