VPLX: Variance Estimation for Complex Samples

VPLX is a FORTRAN 77 program for the calculation of variances for complex sample designs through replication. It is in the public domain. The primary use of VPLX is within the Census Bureau, but it continues to have a number of external users as well.

Two PC versions are available directly from this site. The primary release is for Windows 9x/NT/2000. An earlier Win 3.1 version is also available, but Win 3.1 development has ceased. Both versions are available in executable form, and a Fortran compiler is not required.

A UNIX version is available in the form of Fortran source code. A SUN/Solaris version of the executable is also offered. If the executable is not compatible with the user's system, a Fortran compiler (f77 or f90) will be required to install VPLX.

VPLX evolved within an original syntactic design. To improve the usability of VPLX, a three-phase plan to improve the syntax began in 1997. Version 1998.09 reflects the results of the first phase of revision. It has received considerable internal testing at the Census Bureau, and it is now the primary production release. The site now emphasizes this version. A beta version from the second phase is currently being tested internally, and it will be posted here when released.

The revisions are designed to maintain upward compatibility, so that new versions will continue to run legacy applications.

• General Description - Please read this information first.

• Documentation - Electronic Documentation (Adobe Acrobat). This should also be read before attempting to download the pc or unix versions.

• PC versions - Versions available for IBM-compatible PC's, both for Win 3.1 and Win 95/NT/2000

• Unix version - Fortran source, Sun Solaris executable, and related information for unix systems.