The MODEL statement specifies the dependent variable and independent regressor variables for the regression model.
You can specify the following options after a slash (/).

LIMIT1=ZERO VARYING

specifies the restriction of the threshold value of the first category when the ordinal probit or logit model is estimated.
LIMIT1=ZERO is the default option. When LIMIT1=VARYING is specified, the threshold value is estimated.

NOINT

suppresses the intercept parameter.
Endogenous Variable Options
The endogenous variable options are the same as the options that you can specify in the ENDOGENOUS statement. If you specify
an ENDOGENOUS statement, all endogenous options in the MODEL statement are ignored.
Endogeneity and Overidentification Test Options
The endogeneity and overidentification test options are the same as the options that you can specify in the ENDOGENOUS statement.
If you specify an ENDOGENOUS statement, all endogeneity and overidentification test options in the MODEL statement are ignored.
BOXCOX Estimation Options

BOXCOX (optionlist )

specifies options that are used for BoxCox regression or regressor transformation. For example, the BoxCox regression is
specified as
model y = x1 x2 / boxcox(y=lambda,x1 x2)
PROC QLIM estimates the following BoxCox regression model:
The optionlist takes the form variablelist < = varname > separated by commas. The variablelist specifies that the list of variables have the same BoxCox transformation; varname specifies the name of this BoxCox coefficient. If varname is not specified, the coefficient is called _Lambdai, where i increments sequentially.
Variable Selection Options

SELECTVAR <=(selectvaroption)>

enables variable selection. The selectvaroption specifies a variable selection method based on an information criterion. For more information, see the section Variable Selection. You can specify the following selectvaroptions:

DIRECTION=FORWARD  BACKWARD

specifies the searching algorithm to use in the variable selection method. By default, DIRECTION=FORWARD.

CRITER=AIC  SBC

specifies the information criterion to use for the variable selection. By default, CRITER=AIC.

MAXSTEPS=value

specifies the maximum number of steps that are allowed in the search algorithm. The default is infinite; that is, the algorithm
does not stop until the stopping criterion is satisfied.

LSTOP=value

specifies the stopping criterion. The value represents the percentage of decrease or increase in the AIC or SBC that is required for the algorithm to proceed; it must
be a positive number less than 1. The default is 0.

RETAIN(regressors)

specifies a list of regressors that are to be retained in any model that the variable selection process considers.
The following rules apply to how regressors are handled when you specify more than one MODEL statement and use the SELECTVAR
option:

If you do not specify the SELECTVAR option in a particular MODEL statement, then all regressors in the original model are
included in any model that the variable selection algorithm considers. In other words, omitting the SELECTVAR option is equivalent
to providing the option: SELECTVAR=(RETAIN(allregressors)).

If you specify the SELECTVAR option without any =(option) clause in a MODEL statement, then all regressors in that model (other than the intercept, if present) are eligible for potential
exclusion as the variable selection process is executed.
The following example specifies 10 possible regressor candidates, out of which five are selected using the AIC criterions:
proc qlim data=one;
model y = x1x10 /selectvar=(direction=forward criter=AIC maxsteps=5);
run;