You are here: CTSPedia>CTSpedia Web>StatisticalTools>SasTools>CountRegressionSASMacro (15 Jul 2010, RuiChen)EditAttach

MacroHeaderForm edit

Macro Name

Countreg

Description This is a macro for performing Poisson regression for count data. The macro will automatically check for overdipersion based on the scale parameter. If the estimated scale parameter (computed either by deviance or by Pearson chi-square, whichever is bigger) is larger than the cutpoint (specified by users), alternative model (such as Sandwich variance estimate using GEE or negative binomial regression) is also provided.
Macro Parameters DSName: Name of SAS data set.
Dir: Directory where the output file is saved. If it is unspecified, the output file is saved under C:\ (Windows) or Home directory (Linux).
ID: Name of the variable for object ID.
Outcome: Name of outcome variable.
PredictNum: Name of the continuous covariates.
PredictClass: Name of the categorical covariates. The reference could be specified using SAS syntax. For example, gender(ref="female") is allowed. Make sure there is no space between the variable name and reference specification. For example, gender (ref="female") is NOT acceptable.
Format: Formats of the variables with with the same order in PredictClass. if no format defined for the corresponding qualitattive variable, a dot (.) must be input as a place holder.
ScaleCutpoint: Cutpoint for the scale parameter to be considered overdispersion
AlternateMod: Alternative model is overdispersion is detected
-GEE: Sandwich variance-covariance estimate.
-NB: Negative binomial regression.
-ZIP: Zero Inflated Poisson regression.
OutForm: Format of output file. HTML or RTF.
Programmer Rui Chen
Revision July 15, 2010 (updated)
Disclaimer This SAS macro is developed by Rui Chen and other members in the Department of Biostatistics and Computational Biology at the University of Rochester under the auspice of the CTSI BERD with the intent to facilitate data analyses and reporting in clinical and related research. It is copyrighted by Dr. Chen, July, 2009 and distributed for free public access.
Example(s) ExsampleRun.sas: An example to execute the Countreg macro.
CountregOutput.htm: The output file produced by the example program
Special Features Checking overdispersion and provide an alternative modeling result
Called Macros %words
Notes

See Also %RegMacro
%Logistic
Edit | Attach | Print version | History: r2 < r1 | Backlinks | Raw View | Raw edit | More topic actions
Topic revision: r2 - 15 Jul 2010 - 08:48:11 - Main.RuiChen
 
Copyright &© by the contributing authors. All material on this collaboration platform is the property of the contributing authors.
Ideas, requests, problems regarding CTSPedia? Send feedback