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Help on trpois0                                               Hilbe 14Dec1997
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0-Truncated Poisson regression

Command line:

  ^trpois0^ depvar [varlist] [weight] [^if^ exp] [^in^ range]  
  [, ^lt(^#^) ir^r ^off(^var^) nol^og^ rob^ust ^score^(var)^ cl^uster(var)]
  

^lt(#)^        = tolerance for convergence
^irr^          = parameter estimates displayed in exponential form; standard 
                 errors and CIs adjusted
^off(str)^     = offset variable - log raw var prior to using as offset
^nolog^        = no display of iteration log
^robust^       = displays robust variance estimator; auto w cluster
^cluster(str)^ = identifies variable used for clustering 
^score(str)^   = creates a variable with score value


Results may be redisplayed by entering the command. Exponential form and 
C.I. level are allowed as options without reestimation.

Use: A 0-truncated Poisson model is appropriate when modeling count data
     which does not have values of 0. This is to be distinguished from
     data sets without 0 values, but which may have 0's. For example,
     length of hospital stay data (LOS) begins with patients having a
     LOS of 1. 0 values are not allowed. This is a situation where a
     truncated model is appropriate.
     
Examples
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 . ^trpois0 studytim died drug2 drug3, irr nolog^
 
 . ^trpois0 infected cases cd4 cd8, nolog irr off(cases) cluster(prov)^

 . ^trpois0, level(90)^    [redisplay]

Also see
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Manual:  [5s] poisson, glm, cnreg
On-line:  help for @poisson@, @glm@, @cnreg@

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Joseph Hilbe
Arizona State University
atjmh@@asuvm.inre.asu.edu 
jhilbe@@aol.com