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help for ^cepois^
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Censored Poisson Regression
------------------------------
^cepois^ depvar [varlist] [weight] [^if^ exp] [^in^ range]
[, ^cen^sor(^var^)^ l^evel ^eform^ ^off^set(^var^)
^e^xposure(^var^) ^R^obust ^CL^uster(^var^) ]
The ^censor^ option is required. If no observations are censored,
all values of the censor variable have the value of ^1^. Left
censoring is indicated with censor values of ^0^; right
censoring with values of ^-1^. A non-censored model is identical
to a Poisson model.
^fweights^, ^aweights^, and ^pweights^ are allowed; see help @weights@.
Options
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^level^(^#^) specifies the confidence level, in percent, for confidence
intervals. The default is ^level^(^95^) or as set by ^set level^.
^eform^ reports estimated coefficients transformed to incidence ratios, i.e.,
e to the power of b rather than b. Standard errors and confidence intervals
are similarly transformed. This option affects how results are displayed,
not how they are estimated.
^offset^(^varname^) specifies a variable that is to be entered
directly into the log-link function with coefficient constrained to be 1.
One must log (ln) the offset variable prior to entering it as an offset.
^exposure^(^varname^) specifies a variable that is to be entered
directly into the log-linked function. ^exposure^ is the natural log
of the variable entered as an offset.
^robust^ specifies that the Huber/White/sandwich estimator of variance is
to be used in place of the traditional calculation; see [U] 23.14
Obtaining robust variance estimates. robust combined with cluster()
allows observations which are not independent within cluster (although
they must be independent between clusters).
^cluster^(^varname^) specifies that the observations are independent across
groups (clusters) but not necessarily within groups. varname specifies
to which group each observation belongs; e.g., ^cluster^(^personid^) in data
with repeated observations on individuals. cluster() can be used with
pweights to produce estimates for unstratified cluster-sampled data, but
see help svypoisson for a command especially designed for survey data.
Specifying cluster() implies robust.
Examples
--------
. ^cepois studytim died drug2 drug3, censor(cenvar) eform ^
. ^cepois infected cases cd4 cd8 [pw=citysize], eform e(cases)^
Author
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^Joseph Hilbe^
Arizona State University
jhilbe@@aol.com
^11Aug2004^
Also see
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Manual: [R] poisson, glm
On-line: help for @poisson@, @glm@