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help for xtpqml
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 Fixed-effects Poisson (Quasi-ML) regression with Robust Standard Errors

        xtpqml depvar [indepvars] [if exp] [in range], fe i(varname) irr
                      cluster(varname)]


    by ... : may be used with xtpqml; see help by.

    Weights are not allowed.


Description

    xtpqml is simply a wrapper for the xtpoisson command that computes robust
    standard errors.

    Persons interested in this regression model should also see help 
    xtpoisson, and help poisson.


Options

    i(varname) is not optional; it specifies the (numeric) identifier
        variable for groups in the panel data. This option can be set using 
        iis.

    irr reports the estimated coefficients transformed to incident rate
        ratios, i.e., exp(b) rather than b.  Standard errors and confidence
        intervals are similarly transformed.  This option affects how results
        are displayed, not how they are estimated.

    cluster allows for cross-sectional clustering of residuals at a more
        aggregated level than the individual fixed effect. This is an unusual
        assumption and users are responsible for providing their own
        interpretation of the results obtained by specifiying this option


Examples

    . xtpqml y x, i(id)

    . xtpqml y x, fe i(id)

    . xtpqml y x, i(id) irr

    . xtpqml y x, i(id) cluster(group)



Also see

    Manual:  [U] 23 Estimation and post-estimation commands,
             [XT] xtpoisson