[email protected]
>
> This is the first time that I have worked with the user
> generated "fit stat" program. I wondered if anyone out
> there could offer me some insight as to why none of the R2
> measures are appearing for my "Poisson" syntax below?
>
> Thanks in advance for any help,
> Beth
>
> . poisson falls180 mdscog m210 chairfast m083 m214 m148
> mdsfalls180 m277 m278 m
> > 297 if los2groups==0, exposure (los91to180) cluster
> (facil) nolog irr
>
> Poisson regression Number of
> obs = 711
> Wald chi2(10) = 142.61
> Log likelihood = -1674.5029 Prob >
> chi2 = 0.0000
>
> (standard errors adjusted for clustering on facil)
>
> | Robust
> falls180 | IRR Std. Err. z P>|z| [95%
> Conf. Interval]
>
> mdscog | 1.026908 .023846 1.14 0.253
> .9812187 1.074725
> m210 | .1426514 .1045136 -2.66 0.008 .0339346
> .5996653
> chairfast | .718835 .1113207 -2.13 0.033
> .5306521 .9737523
> m083 | .3330169 .1318824 -2.78 0.005 .1532395
> .7237053
> m214 | 1.001907 .1976512 0.01 0.992 .6806227
> 1.474851
> m148 | 1.403981 .2481918 1.92 0.055 .9928604
> 1.985337
> mdsfalls180 | 2.19444 .2702449 6.38 0.000
> 1.723845 2.793502
> m277 | .9953168 .181114 -0.03 0.979 .6967412
> 1.421842
> m278 | 1.673501 .3274209 2.63 0.008 1.140482
> 2.455635
> m297 | 1.033173 .1391611 0.24 0.809 .7934548
> 1.345314
> los91to180 | (exposure)
>
> . fitstat
>
> Measures of Fit for poisson of falls180
>
> Log-Lik Intercept Only: . Log-Lik Full
> Model: -1674.503
> D(700): 3349.006 LR(10):
> .
> Prob > LR: .
> McFadden's R2: . McFadden's Adj R2:
> .
> Maximum Likelihood R2: . Cragg & Uhler's
> R2: .
> AIC: 4.741 AIC*n:
> 3371.006
> BIC: -1247.665 BIC':
>
I'm not very familiar with these models but all seems to
stem from the absence of a measure for log-likelihood intercept only
which is in turn a consequence of your specification of
-exposure()-. In short, your model means that these measures
cannot be computed.
Nick
[email protected]
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