
               The COUNTREG procedure is controlled by the following statements:
                         PROC COUNTREG
                          options   ; 
                         BOUNDS
                          bound1 < , bound2 …>   ; 
                         BY
                          variables   ; 
                         CLASS
                          variables   ; 
                         FREQ
                          variable   ; 
                         INIT
                          initvalue1 <, initvalue2 …>   ; 
                         MODEL
                          dependent variable = regressors / options   ; 
                         NLOPTIONS
                          options   ; 
                         OUTPUT
                          options   ; 
                         RESTRICT
                          restriction1 <, restriction2 …>   ; 
                         WEIGHT
                           variable    ; 
                         ZEROMODEL
                          dependent variable 
                 
                 
                zero-inflated regressors / options   ; 
            
There can only be one MODEL statement. The ZEROMODEL statement, if used, must appear after the MODEL statement, and the CLASS statement must precede the MODEL statement. If a FREQ or WEIGHT statement is specified more than once, the variable specified in the first instance is used.