The COUNTREG Procedure
- Overview
- Getting Started
-
Syntax
Functional SummaryPROC COUNTREG StatementBAYES StatementBOUNDS StatementBY StatementCLASS StatementDISPMODEL StatementFREQ StatementINIT StatementMODEL StatementNLOPTIONS StatementOUTPUT StatementPERFORMANCE StatementPRIOR StatementRESTRICT StatementSCORE StatementSHOW StatementSTORE StatementWEIGHT StatementZEROMODEL Statement -
DetailsSpecification of RegressorsMissing ValuesPoisson RegressionConway-Maxwell-Poisson RegressionNegative Binomial RegressionZero-Inflated Count Regression OverviewZero-Inflated Poisson RegressionZero-Inflated Conway-Maxwell-Poisson RegressionZero-Inflated Negative Binomial RegressionVariable SelectionPanel Data AnalysisBY Groups and Scoring with an Item StoreComputational ResourcesNonlinear Optimization OptionsCovariance Matrix TypesDisplayed OutputBayesian AnalysisPrior DistributionsAutomated MCMC AlgorithmOUTPUT OUT= Data SetOUTEST= Data SetODS Table NamesODS Graphics
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Examples
- References
The RESTRICT statement imposes linear restrictions on the parameter estimates. You can specify any number of RESTRICT statements.
Each restriction is written as an expression, followed by an equality operator (=) or an inequality operator (<, >, <=, >=), followed by a second expression:
expression operator expression
The operator can be =, <, >, <=, or >=.
Restriction expressions can be composed of parameter names, constants, and the operators times (
), plus (
), and minus (
). The restriction expressions must be a linear function of the parameters. For continuous regressors, the names of the parameters
are the same as the corresponding variables. For a regressor that is a CLASS variable, the parameter name combines the corresponding
CLASS variable name with the variable level. For interaction and nested regressors, the parameter names combine the names
of each regressor. The names of the parameters can be seen in the OUTEST= data set.
Lagrange multipliers are reported in the “Parameter Estimates” table for all the active linear constraints. They are identified
with the names Restrict1, Restrict2, and so on. The probabilities of these Lagrange multipliers are computed using a beta distribution (LaMotte, 1994). Nonactive (nonbinding) restrictions have no effect on the estimation results and are not noted in the output.
The following RESTRICT statement constrains the negative binomial dispersion parameter 
to 1, which restricts the conditional variance to be 
:
restrict _Alpha = 1;
The RESTRICT statement is not supported if you also specify a BAYES statement. In Bayesian analysis, the restrictions on parameters are usually introduced through the prior distribution.