SSI’s parent company, Vector Psychometric Group, LLC, released IRTPRO 5.
IRTPRO™ is an application for comprehensive item calibration and test scoring using IRT models. IRTPRO™ was first released in 2010. The current version of IRTPRO™ is Version 5.0 (released date: June 17, 2020).
As of June 17, 2020, IRTPRO™ is no longer marketed by SSI. Instead, SSI’s parent company, Vector Psychometric Group, LLC, is exclusively marketing IRTPRO™ under a subscription-based software delivery and support model. Please visit the updated online store at https://store.vpgcentral.com/ to purchase a subscription or to manage your IRTPRO license.
IRT models for which item calibration and scoring are implemented in IRTPRO™ are based on unidimensional and multidimensional [confirmatory factor analysis (CFA) or exploratory factor analysis (EFA)] versions of the widely used response functions such as 1PL, 2PL, 3PL, graded, generalized partial credit, and nominal. More information about IRTPRO™ can be found at irtpro.com.
All questions about IRTPRO™ sales should be directed to sales@vpgcentral.com. Feel free to continue to write to irt@ssicentral.com if you have any technical questions about IRTPRO™ (Version 2 – Version 4). IRTPRO™ 5+ users should write to the new, dedicated IRTPRO™ customer support desk at irtpro@vpgcentral.com.