Cutting edge software. Empowering research since 1971.

SSI Live™ Subscription

Meet our new product delivery and support system. Compare with old licensing model.

Hierarchical Modeling

For more than 3 decades, HLM has defined the practice in modeling hierarchical data.

Structural Equation Modeling

LISREL is the progenitor of structural equation modeling, since 1976.

Item Response Theory

BILOG-MG and PARSCALE have enabled IRT applications in educational measurement.

Mixed Modeling

SuperMix offers advanced linear and nonlinear mixed effects modeling for biostatistics.

Growth Modeling

Fast, comprehensive analysis of longitudinal human growth data with Auxal.

LISREL 10.3 now available on SSI Live™

SSI is pleased to announce the immediate availability of new...

Announcing the Release of AUXAL 4

A new version of the AUXAL program is immediately available...

Announcing the Release of BILOG-MG 4

A new version of the BILOG-MG program is immediately available....

Announcing the release of SuperMix

A new version of the SuperMix program is immediately available....

Announcing the release of PARSCALE 5

A new version of the PARSCALE program is immediately available....

VPG Releases New Version of IRTPRO

SSI's parent company, Vector Psychometric Group, LLC, released IRTPRO 5....

HLM 8 Now Available on SSI Live™

HLM transitions to the SSI Live™ software-as-subscription service. We are...

SSI Acquired by Vector Psychometric Group

Scientific Software International Inc. is acquired by Vector Psychometric Group....

Introducing New Features in HLM 8

The HLM8 program has a number of new statistical features....