The NLIN Procedure

ODS Graphics

Statistical procedures use ODS Graphics to create graphs as part of their output. ODS Graphics is described in detail in Chapter 21: Statistical Graphics Using ODS.

Before you create graphs, ODS Graphics must be enabled (for example, by specifying the ODS GRAPHICS ON statement). For more information about enabling and disabling ODS Graphics, see the section Enabling and Disabling ODS Graphics in Chapter 21: Statistical Graphics Using ODS.

The overall appearance of graphs is controlled by ODS styles. Styles and other aspects of using ODS Graphics are discussed in the section A Primer on ODS Statistical Graphics in Chapter 21: Statistical Graphics Using ODS.

PROC NLIN assigns a name to each graph it creates using ODS. You can use these names to refer to the graphs when using ODS. The graphs that are controlled by the PLOTS option in the PROC NLIN statement are listed in Table 69.10, those that are controlled by the options in PROFILE statement are in Table 69.11.

Table 69.10: Graphs Controlled by the PLOTS option in the PROC NLIN Statement

ODS Graph Name

Plot Description

PLOTS Option

ContourFitPlot

Contour fit plot for models with two regressors

FIT

FitPlot

Fit plot for models with one regressor

FIT

FitDiagnosticsPanel

Panel of fit diagnostics

DIAGNOSTICS

LeveragePlot

Tangential and Jacobian leverages versus observation number

DIAGNOSTICS

LocalInfluencePlot

Local influence versus observation number

DIAGNOSTICS

ObservedByPredictedPlot

Dependent variable versus predicted values

DIAGNOSTICS(UNPACK)

ProjectedResidualHistogram

A histogram of the projected residuals

DIAGNOSTICS(UNPACK)

RawResidualExpectationPlot

Raw residual expectation versus predicted values

DIAGNOSTICS(UNPACK)

RawResidualHistogram

A histogram of the raw residuals

DIAGNOSTICS(UNPACK)

ResidualBoxPlot

A box plot of the raw and projected residuals

DIAGNOSTICS(UNPACK)

ResidualPanel

A panel of the raw and projected residuals versus the regressors

RESIDUALS

ResidualPlot

A plot of the raw and projected residuals versus the regressors

RESIDUALS(UNPACK)

ResidualByPredictedPlot

Raw and projected residuals versus the predicted values

DIAGNOSTICS(UNPACK)

RStudentByJacLeveragePlot

Standardized raw and projected residuals versus Jacobian leverage

DIAGNOSTICS(UNPACK)

RStudentByPredictedPlot

Standardized raw and projected residuals versus the predicted values

DIAGNOSTICS(UNPACK)

RStudentByTanLeveragePlot

Standardized raw and projected residuals versus tangential leverage

DIAGNOSTICS(UNPACK)


Table 69.11: Graphs Controlled by the PROFILE Statement

ODS Graph Name

Plot Description

PROFILE Option

ConfidenceCurve

Parameter value versus t value

CONFCURV

JackknifePlot

Absolute relative percentage difference versus observation number

JACKKNIFE

ProfiletPlot

Likelihood ratio pivotal statistic versus Wald pivotal statistic

TPLOT


Table 69.12: Graphs Controlled by the BOOTSTRAP Statement

ODS Graph Name

Plot Description

BOOTSTRAP Option

BootstrapHistPlot

A histogram of bootstrap parameter estimates

BOOTPLOTS(HIST)

BootstrapScatterPlot

Pairwise scatter plot of bootstrap parameter estimates

BOOTPLOTS(SCATTER)


Convergence Status Table

The "Convergence Status" table can be used to programmatically check the status of an estimation. This table contains the Status variable that takes on the value 0, 1, 2, or 3. If Status takes on a value less than 3, the convergence criterion was met. Specifically, the values mean the following:

Status=0

indicates that the convergence criterion was met and no warning or error messages were issued during the PROC NLIN run. Also, no notes that could indicate a problem with the model were issued.

Status=1

indicates that the convergence criterion was met and notes were written to the log that might indicate a problem with the model.

Status=2

indicates that the convergence criterion was met and one or more warning messages were produced during the PROC NLIN run.

Status=3

indicates that the convergence criterion was not met.

The following sample program demonstrates how the "Convergence Status" table can be used:

ods output ConvergenceStatus=ConvStatus;
proc nlin data=YourData;
   parameters a=1 b=1 c=1;
   model wgt = a + x / (b*y+c*z);
run;

data _null_;
   set ConvStatus;
   if status > 0 then put "A problem occurred";
run;