MODEL Statement

The following new or updated options are available in the MODEL statement after a slash (/).

DETAILS < ( tables ) >

selects which tables to display, where tables is one or more of KDTREE, MODELSUMMARY, OUTPUTSTATISTICS, and PREDATVERTICES:

KDTREE displays the kd tree structure.
MODELSUMMARY displays the fit criteria for all smoothing parameter values that are specified in the SMOOTH= option in the MODEL statement, or which are fit with automatic smoothing parameter selection.
OUTPUTSTATISTICS displays the predicted values and other requested statistics at the points in the input data set.
PREDATVERTICES displays fitted values and coordinates of the kd tree vertices where the local least squares fitting is done.

The KDTREE and PREDATVERTICES specifications are ignored if the DIRECT option is specified in the MODEL statement. Specifying the option DETAILS with no qualifying list outputs all tables.

INTERP= LINEAR | CUBIC

specifies the degree of the interpolating polynomials used for blending local polynomial fits at the kd tree vertices. This option is ignored if the DIRECT option is specified in the model statement. INTERP=CUBIC is not supported for models with more than two regressors. The default is INTERP=LINEAR.

TRACEL

specifies that the trace of the prediction matrix as well as the GCV and AICC statistics are to be included in the "FIT Summary" table. The use of any of the MODEL statement options ALL, CLM, DFMETHOD=EXACT, DIRECT, SELECT=, or T implicitly selects the TRACEL option.

SELECT=criterion < ( <GLOBAL> <STEPS> <RANGE(lower,upper)> )>

specifies that automatic smoothing parameter selection be done using the named criterion, where the criterion is one of AICC, AICC1, or GCV. The smoothing parameter value is selected to yield a minimum of the criterion, as follows:

If you specify the SMOOTH=value-list option, then PROC LOESS selects the largest value in this list that yields the global minimum of the specified criterion.
If you do not specify the SMOOTH= option, then PROC LOESS finds a local minimum of the specified criterion using a golden section search of values less than or equal to one.

You can specify the following modifiers in parentheses after the specified criterion to alter the behavior of the SELECT= option:

GLOBAL specifies that a global minimum be found within the range of smoothing parameter values examined. This modifier has no effect if you also specify the SMOOTH= option in the MODEL statement.
STEPS specifies that all models evaluated in the selection process be displayed.
RANGE(lower,upper) specifies that only smoothing parameter values greater than or equal to lower and less than or equal to upper be examined.

For models with one dependent variable, if you specify neither the SELECT= nor the SMOOTH= options in the MODEL statement, then PROC LOESS uses SELECT=AICC.

The following table summarizes how the smoothing parameter values are chosen for various combinations of the SMOOTH= option, the SELECT= option, and the SELECT= option modifiers.

Table 6.1: Smoothing Parameter Value(s) Used for Combinations of SMOOTH= and SELECT= Options for Models with One Dependent Variable

Syntax	Search Method	Search Domain
default	golden section using AICC	(0,1]
SMOOTH=list	no selection	values in list
SMOOTH=list SELECT=criterion	global	values in list
SMOOTH=list SELECT=criterion ( RANGE(l,u) )	global	values in list within [l,u]
SELECT=criterion	golden section	(0,1]
SELECT=criterion ( RANGE(l,u) )	golden section	[l,u]
SELECT=criterion ( GLOBAL )	global	(0,1]
SELECT=criterion ( GLOBAL RANGE(l,u) )	global	[l,u]

Note: The SELECT= option cannot be used for models with more than one dependent variable.

SMOOTH=value-list

specifies a list of positive smoothing parameter values. If you do not SELECT= option in the MODEL statement, then a separate fit is obtained for each SMOOTH= value specified. If you do specify the SELECT= option, then models with all values specified in the SMOOTH= list are examined, and PROC LOESS selects the value that minimizes the criterion specified in the SELECT= option.

For models with two or more dependent variables, if the SMOOTH= option is not specified in the MODEL statement, then SMOOTH=0.5 is used as a default.