Summary of survey software: VPLX

NOTE: The following information was summarized from information in the program documentation, and was not directly provided by the developer. Potential users are advised to download the documentation for further information.


U.S. Bureau of the Census: Dr. Robert Fay.

Types of designs that can be accommodated.

Stratified and clustered designs.

Types of estimands and statistical analyses that can be accommodated.

VPLX calculates summary statistics (means, proportions, and totals for the entire sample or by subclasses) and their standard errors. It can be used to calculate a valid t-test. Arithmetical transformations of the data can be specified in the command language, which means that standard errors can be calculated for arbitrary sums, differences, products, and quotients.

Restrictions on number of variables or observations.

Primary methods used for variance estimation.

Replication methods, primarily the jackknife. Half-sample replication and random group replication are also available, and the weights associated with these schemes may be modified by the user.

General description of the "feel" of the software.

VPLX is a standalone program with its own command language. Data are stored in a special file structure which includes "metadata" describing the sampling design; they can be read in from standard text files.

Platforms on which the software can be run.

For Windows PCs, a precompiled version is available, which runs under Windows from the command line.
For Unix systems, Fortran source code is available the site; a Fortran (f77) compiler is required to make the executable. A precompiled version for Sun Solaris systems is available.
VPLX has also been compiled for other platforms, such as VMS systems, although these versions are not currently maintained. Contact the developer for more information.

Availability, pricing and terms.

Free (public domain) software, available to the public at the site described below.

Contact information.

To download program and documentation contact:
The developer of VPLX is Dr. Robert Fay,

Additional information.

This software is discussed in the review article from The Survey Statistician.
See also Fay (1990), "VPLX: Variance Estimates for Complex Samples," Proceedings of the Survey Research Methods Section, ASA, 266-271.

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