This release brings several new procedures to SAS/STAT software. The MI and MIANALYZE procedures implement the multiple imputation strategy for missing data. Experimental in Releases 8.1 and 8.2, these procedures are now production. The ROBUSTREG procedure analyzes data that may include outliers; it provides stable results in their presence. The TPHREG procedure is a test release of the PHREG procedure that incorporates the CLASS statement.
Power and sample size computations also become available in SAS 9.1. New procedures POWER and GLMPOWER provide these computations for a number of analyses, and the Power and Sample Size Application surfaces them through a point-and-click interface.
SAS 9.1 introduces two new procedures for the analysis of survey data. The SURVEYFREQ procedure produces one-way to n -way frequency and crosstabulation tables for data collected from surveys. These tables include estimates of totals and proportions (overall, row percentages, column percentages) and the corresponding standard errors. The SURVEYLOGISTIC procedure performs logistic regression for survey data, and it can also fit links such as the cumulative logit, generalized logit, probit, and complementary log-log functions. Both of these procedures incorporate complex survey sample designs, including designs with stratification, clustering, and unequal weighting , in their computations.
In addition, this release includes numerous enhancements to existing procedures. For example, conditional logistic regression is available in the LOGISTIC procedure through the new STRATA statement, and scoring of data sets is available through the new SCORE statement. The GLM procedure now provides the ability to form classification groups using the full formatted length of the CLASS variable levels. In addition, the SURVIVAL statement in the LIFETEST procedure enables you to create confidence bands (also known as simultaneous confidence intervals) for the survivor function S ( t ) and to specify a transformation for computing the confidence bands and the pointwise confidence intervals.
More information about the changes and enhancements to SAS/STAT software follows . Features new in SAS 9.1 are indicated with a 9.1 icon; other features were available with SAS 9. Details can be found in the documentation for the individual procedures.
Selected functionalities in the GLM, LOESS, REG, and ROBUSTREG procedures have been multithreaded to exploit hardware with multiple CPUs. Refer to Cohen (2002) for more details.
A number of SAS/STAT procedures are using an experimental extension to the Output Delivery System (ODS) that enables them to create statistical graphics automatically. The facility is invoked when you include an ODS GRAPHICS statement before your procedure statements. Graphics are then created automatically, or when you specify procedure options for graphics. Procedures taking advantage of ODS graphics are the ANOVA, CORRESP, GAM, GENMOD, GLM, KDE, LIFETEST, LOESS, LOGISTIC, MI, MIXED, PHREG, PLS, PRINCOMP, PRINQUAL, REG, ROBUSTREG, and TPSLINE procedures. The plots produced and the corresponding options are described in the documentation for the individual procedures.