Summary of survey software:
Research Triangle Institute
Types of designs that can be accommodated.
Multiple design options allow users to analyze data from stratified,
cluster sample, or multistage sample designs. Sample members may have
been selected with unequal probabilities, and either with or without
replacement. Any number of strata and stages can be specified. In
addition, different design options may be combined in one study if
different sampling methods were used for parts of the population.
Types of estimands and statistical analyses that can be accommodated.
SUDAAN includes the following statistical procedures:
MULTILOG: Fits multinomial logistic regression models to ordinal and
nominal categorical data and computes hypothesis tests for model
parameters. Estimates odds ratios and their 95% confidence intervals
for each model parameter. Has GEE (Generalized Estimating Equation)
modeling capabilities for efficient parameter estimation.
REGRESS: Fits linear regression models to continuous outcomes and
performs hypothesis tests concerning the model parameters.
LOGISTIC: Fits logistic regression models to binary data and computes
hypothesis tests for model parameters. Estimates odds ratios and their
95% confidence intervals for each model parameter.
SURVIVAL: Fits proportional hazards (Cox regression) models to
failure time data. Estimates hazard ratios and their 95% confidence
intervals for each model parameter.
CROSSTAB: Computes frequencies, percentage distributions, odds
ratios, relative risks, and their standard errors (or confidence
intervals) for user-specified cross-tabulations, as well as chi-square
tests of independence and the Cochran-Mantel-Haenszel chi-square test
for stratified two-way tables.
DESCRIPT: Computes estimates of means, totals, proportions,
percentages, geometric means, quantiles, and their standard errors.
Also computes standardized estimates and tests of single
degree-of-freedom contrasts among levels of a categorical variable.
RATIO: Computes estimates and standard errors of generalized ratios
of the form (Summation y) / (Summation x), where x and y are observed
variables. Also computes standardized estimates and tests
single-degree-of-freedom contrasts among levels of a categorical
The EFFECT statement allows users to specify contrasts of regression
coefficients and hypothesis tests using simple effect names.
Restrictions on number of variables or observations.
Primary methods used for variance estimation.
The Taylor series linearization method (GEE for regression models) is
used combined with variance estimation formulas specific to the sample
design. The user does not need to develop special replicate weights
since the sample design can be specified directly to the program.
Jackknife and Balanced Repeated Replication (BRR) variance estimation is
General description of the "feel" of the software.
SUDAAN uses a SAS-like language. There are two versions of Sudaan with
different data interfaces:
In either case, the same programming language is used.
- "SAS-callable" Sudaan: SUDAAN is called directly as a SAS procedure.
- "Standalone Sudaan": Independent program that reads external file formats, including SAS files or SPSS files.
Platforms on which the software can be run.
SUDAAN is distributed as a precompiled program.
- PCs under Windows 95 or later versions. This is now the primary platform
- Sun SPARC computers under Solaris 2.6 and up.
Availability, pricing and terms.
Release 8.0 of Sudaan is the current version (see list of enhanced
SUDAAN is available under annual site licenses. Annual academic site
license renewal prices range from $60 to $385 per user (depending on
volume), with new licenses costing about twice as much. Government and
commercial annual site license prices range from $65 to $735 per user
depending on product and volume See pricing details at Sudaan
SUDAAN Product Coordinator
Research Triangle Institute
3040 Cornwallis Road
Research Triangle Park NC 27709-2194
SUDAAN offers public 2-day or 3-day training classes several times
each year. Classes can also be taught at user sites.
The following papers about Sudaan are available on-line:
An extensive on-line help library is included for interactive use.
This software is discussed in the review
article from The Survey Statistician.
See also Shah and Barnwell (1993), "Recent developments and future
plans for SUDAAN" in Proceedings of the Survey Research Methods
Section, ASA, 657-661.
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