The GAMMOD Procedure

PROC GAMMOD Features

• estimates the regression parameters of a generalized additive model that has fixed smoothing parameters by using penalized likelihood estimation

• estimates the smoothing parameters of a generalized additive model by using either the performance iteration method or the outer iteration method

• estimates the regression parameters of a generalized linear model by using maximum likelihood techniques

• tests the total contribution of each spline term based on the Wald statistic

• provides model-building syntax in the CLASS statement and effect-based parametric effects in the MODEL statement, which are used in other SAS/STAT analytic procedures (in particular, the GLM, LOGISTIC, GLIMMIX, and MIXED procedures)

• provides response-variable options

• enables you to construct a spline term by using multiple variables

• provides control options for constructing a spline term, such as fixed degrees of freedom, initial smoothing parameter, fixed smoothing parameter, smoothing parameter search range, user-supplied knot values, and so on

• provides multiple link functions for any distribution

• provides a WEIGHT statement for weighted analysis

• provides a FREQ statement for grouped analysis

• provides an OUTPUT statement to produce a data table that has predicted values and other observationwise statistics

• produces graphs via ODS Graphics

• enables you to run on a cluster of machines that distribute the data and the computations

• enables you to run in single-machine mode

• exploits all the available cores and concurrent threads (for information about how PROC GAMMOD uses threads, see the section Multithreading in Chapter 3: Shared Concepts)