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help for svrcorr
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Correlations of variables for survey data, with with replication-based standard
>  errors


        svrcorr  [varlist] [if exp] [in range] [, pw obs sig print(#) star(#)
                 bonferroni sidak


by ... : may be used with the above commands; see by.


Description

svrcorr displays the correlation matrix for varlist or, if varlist is not
specified, for all variables in the data.  Observations are excluded from the
calculation due to missing values on a casewise basis, unless the pw option is
specified.

Significance levels of the correlations are based on standard errors that are
calculated using a series of user-supplied replication weights, by balanced
repeated replication (BRR) or the survey jackknife (JK1, JK2, or JKn).  This is
an alternate method to the Taylor series linearization methods used by Stata's 
svy commands.  See survwgt for details on the creation of weights and
estimation of variances with replication.


Options

pw specifies that observations are to be excluded from the calculations on a
    pairwise basis.  The default is casewise.

obs adds a line to each row of the matrix reporting the number of observations
    used in calculating the correlation coefficient.

sig adds a line to each row of the matrix reporting the significance level of
    each correlation coefficient.

print(#) specifies the significance level of correlation coefficients to be
    printed.  Coefficients with larger significance levels are left blank.
    print(10) or print(.1) would list only coefficients significant at the 10%
    level or better.

star(#) specifies the significance level of coefficients to be starred.
    star(5) or star(.05) would star all coefficients significant at the 5%
    level or better.

bonferroni makes the Bonferroni adjustment to calculated significance levels.
    This affects printed significance levels and the print() and star()
    options.  "pwcorr, print(.05) bonferroni" prints coefficients with
    Bonferroni-adjusted significance levels of .05 or less.

sidak makes the Sidak adjustment to calculated significance levels.  This
    affects printed significance levels and the print() and star() options.
    "pwcorr, print(.05) sidak" prints coefficients with Sidak-adjusted
    significance levels of .05 or less.


Examples

        {inp:. svrcorr dvcrate medage

        . svrcorr mrgrate dvcrate medage, pw obs sig



Methods and formulae

See survwgt for details of the replication methods.

For calculation of variances and significances, the correlations are first
transformed using Fisher's Z transformation, in order to normalize the
distribution.


Saved Results

svrcorr saves in r() the following for the last-calculated correlation:

        rho  the estimated correlation coefficient
        N    the number of observations
        p    the p-level


Acknowledgements

These commands consists largely of the ado file code from official Stata's
pwcorr command.  I would like to thank Bobby Gutierrez at StataCorp for advice
on implementation of BRR.


Author

        Nick Winter
        Cornell University
        nw53@cornell.edu