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help for r2o                                                     (Michael Lacy)
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    r2o --      r2o ordinal explained variation statistic

Syntax

        r2o [,TRustme] [NOmarg]

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Description

    r2o calculates the ordinal explained variation statistic (i.e., Rē)
    described by Lacy (2006), which is used to summarize the fit of a
    regression model for an ordinal response. It rests on an ordinal
    variation measure that entails no assumptions about intercategory
    distances or distributional form.  This measure is valid regardless of
    the method used to estimate the model, and was shown to outperform
    various pseudo-Rē measures in estimating the value of the true Rē for a
    regression model for an underlying continuous response, even though its
    sense does not require such.  r2o is to be used after a relevant
    categorical response model has been run, while the e() list is still
    intact. By default, the program recognizes the following as relevant
    response models: ologit, oprobit, mlogit, and gologit2. However, r2o
    should work after any estimation command for which predict p1,..., pk
    will calculate predicted probabilities, and which follows official
    Stata's conventions for naming items in the e() list.


Options
    options           Description
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      trustme          will make the program run regardless of whether an
                        estimation command it recognizes has just been run.
      nomarg           suppresses the display of the marginal distribution of
                        the response variable.

Saved results

r2o saves the following in r():
      r(vtot)         total variation in the response variable
      r(verr)         error variation, i.e., the conditional variation in the
                       response
      r(vmodel)       variation explained by the model
      r(r2o)          ordinal explained variation statistic.
      r(ur2o)         bias adjusted version of r2o.

Examples

    . sysuse auto
    . ologit rep78 price foreign
    . ologit rep78 price foreign, nomarg

References

    Lacy, Michael G. 2006. "An Explained Variation Measure for Ordinal
        Response Models With Comparisons to Other Ordinal Rē Measures."
        Sociological Methods and Research. 34:469-520.


Author

    Michael G. Lacy
    Colorado State University
    Fort Collins, Colorado
    Michael.Lacy@colostate.edu
    http://central.colostate.edu/author/mglacy/

Acknowledgements

    My thanks go to Richard Williams for helping me with various programming
        issues.