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help for ordvar                                                  (Michael Lacy)
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    ordvar --   Ordinal variation and consensus statistics

Syntax

        ordvar varname [if] [in] [,low(#) high(#)]

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 The by prefix is allowed.

Description

    ordvar calculates measures of ordinal consensus and dispersion. These
    include lsq and 1-lsq, which are 0/1 normed ordinal consensus and
    dispersion statistics described in Blair and Lacy (2000). The latter
    statistic is essentially identical to the IOV measure of Berry and Mielke
    (1992).  The non-normed version of the dispersion statistic, termed
    d-squared by Lacy (2006), is also calculated, as are delta-method
    standard errors for these statistics. These measures do not rely on
    assumptions about intercategory distances or distributional form.

Arguments and Options
    varname is the variable for which the dispersion and consensus statistics
    are desired.  This variable is assumed to be coded with consecutive
    integers, starting with the lowest value occurring in the data up to the
    highest. As an option, to allow for situations in which the lowest or
    highest theoretically possible value does not occur in the data, the user
    may specify these values by using the low(#) and high(#) options.
    Failure to specify this option when necessary will give incorrect
    results.

Returned results

    ordvar saves the following in r():

    Scalars    
      r(onemlsq)       1-lsq normed ordinal dispersion statistic
      r(lsq)           lsq normed ordinal dispersion statistic
      r(dsq)           d-squared non-normed ordinal dispersion statistic
      r(dsqse)         standard error of d-squared
      r(lsqse)         standard error of 1-lsq or lsq
 

Examples

    . sysuse auto
    . ordvar rep78
    . // What if some theoretical minimum or maximum value did not occur in
             the data?
    . keep if foreign==1
    . tab1 rep78
    . ordvar rep78, low(1) high(5)


References

    Blair, J. and M. Lacy. 2000. "Statistics of Ordinal Variation."
        Sociological Methods and Research. 28: 251-280.

    Lacy, M. 2006.  "An Explained Variation Measure for Ordinal Response
        Models with Comparisons to Other Ordinal R2 Measures." Sociological
        Methods and Research 34:469-520.

    Berry, K. J. and P. W. Mielke, Jr. 1992. "Assessment of Variation in
        Ordinal Data." Perceptual and Motor Skills 74:63-66.

Author

    Michael G. Lacy
    Colorado State University
    Fort Collins, Colorado
    Michael.Lacy@colostate.edu