Summary of survey software: SAS/STAT

Vendor

SAS Institute Inc.

Types of Designs That Can Be Accommodated

For the sample selection procedure, the sample design can be a complex multistage sample design that includes stratification, clustering, replication, and unequal probabilities of selection.

For survey data analysis procedures, the sample design can be a complex survey sample design with stratification, clustering, unequal weighting, and with or without replacement.

Types of Estimands and Statistical Analyses That Can Be Accommodated

SAS/STAT Software provides the SURVEYSELECT procedure for sample selection and the SURVEYMEANS and SURVEYREG procedures for producing descriptive statistics and regression estimates, respectively. These three procedures are available in SAS versions 8 and higher. Beginning with SAS 9, SAS/STAT also includes the SURVEYFREQ procedure for computing crosstabulations and tests of association, and the SURVEYLOGISTIC procedure for performing logistic regression. The analysis procedures can accommodate complex survey designs that include stratification, clustering, and unequal weighting.

• The SURVEYSELECT procedure provides a variety of methods for selecting probability-based random samples. The procedure can select a simple random sample, or samples with design features such as stratification, clustering or multistage sampling, or unequal probabilities of selection. It can accomodate very large sampling frames. It can draw a replicated sampling, i.e. a sample composed of a set of replicates, each selected in the same way.
  PROC SURVEYSELECT accepts the sampling frame as a SAS data set. Control language specifies the selection methods, the desired sample size or sampling rate, and other parameters. The output data set contains the selected units, with selection probabilities and sampling weights.
• The SURVEYMEANS procedure estimates population totals, means, and ratios (SAS 8.2 and later), with estimates of their variances, confidence limits, and other descriptive statistics, under sample designs that may include stratification, clustering, and unequal weighting.
• The SURVEYREG procedure estimates regression coefficients by generalized least squares, using elementwise regression, assuming that the regression coefficients are the same across strata and PSUs.
• The SURVEYLOGISTIC procedure fits logistic regression models for discrete response survey data by maximum likelihood, incorporating the sample design into the analysis.
• The SURVEYFREQ procedure produces one-way to n-way frequency and crosstabulation tables from sample survey data. These tables include estimates of population totals, population proportions, and corresponding standard errors. Confidence limits, coefficients of variation, and design effects are also available, as are tests of independence (Wald test, Rao-Scott likelihood ratio test, Rao-Scott chi-square test).

Restrictions on Number of Variables or Observations.

None

Primary Methods Used for Variance Estimation.

Taylor expansion.

General Description of the "Feel" of the Software.

The interface is similar to other SAS procedures. Programs may be entered from command files or through a windowing system. The Explorer window is used to view and manage SAS files. The Program Editor is used to enter, edit, and submit SAS programs, and messages appear in the Log window. Output from SAS programs is viewed in the Output window and navigate and managed in the Results window.

Platforms on which the Software Can Be Run.

Version 9.1 of the SAS System is available on the following platforms:

• Aix (64-bit), Release 5.1+
• HP/UX (64-bit), Release 11i+
• HP/UX Itanium (64-bit), Release 11i+
• Linux for Intel (32-bit): Red Hat 8.0, Advanced Server 2.1, SuSE SLES 8
• Linux for Itanium (64-bit): Red Hat RHEL 3.0
• Open VMS Alpha (64-bit), Release 7.2+ (excluding Release 7.3)
• OS/390, Version 2, Release 10
• Solaris (64-bit), Version 8 or 9+
• Tru64 UNIX (64-bit), Version 5.1A or 5.1B
• Windows (32-bit on Intel) Windows NT 4 Server, Windows 2000 Server, Windows Server 2003, Windows XP Professional
• Windows (64-bit on Itanium) Windows Server 2003
• z/OS, Version 1

Availability, Pricing and Terms.

SAS Software is licensed on an annual basis. Please contact the SAS Institute directly for more information.

Contact Information

SAS Institute Inc.
SAS Campus Drive
Cary, NC 27513-2414
USA
Telephone: (919) 677-8000
Fax: (919) 677-4444
SAS Home Page: http://www.sas.com/
Statistics and Operations Research: http://www.sas.com/rnd/app/

Additional Information.

Recent papers and documentation on the survey selection and analysis procedures are available from SAS Institute's Statistics and Operations Research website at http://support.sas.com/rnd/app/da/new/dasurvey.html; see links at bottom of that page for papers and documentation.

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