IRT
 
Academic and non-academic licenses for IRT software products
 
  • SSI, Inc. offers academic and non-academic (production and commercial) licenses for its IRT software products.
  • Academic licenses apply to end users that intend to use the software exclusively for academic research and instruction.
  • Non-academic licenses apply to end users that intend to use the software for assessment.
  • Academic licenses for BILOG-MG, IRTPRO, and PARSCALE for Windows can be purchased by academic end users with legitimate academic email addresses via the SSI Shopping Cart.
  • Single 12 month non-academic licenses for BILOG-MG, IRTPRO, and PARSCALE for Windows can be purchased via the SSI Shopping Cart.
 
IRTPRO 2.1 for Windows by Li Cai, David Thissen & Stephen du Toit
 
 
BILOG-MG 3 by Michele Zimowski, Eiji Muraki, Robert Mislevy & Darrell Bock
 
  • Graphical user interface
  • Efficient analysis of binary items including multiple choice or short-answer items scored right, wrong, omitted, or not-presented
  • Capable of large scale production analysis, and handling of multiple groups
  • Performs item analysis and scoring of any number of subtests or subscales
  • Non-equivalent groups equating
  • Vertical equating of test forms
  • Differential item functioning (DIF)
  • Detection and correction for parameter trends over time (DRIFT)
  • Calibration and Scoring of tests in two-stage testing procedures
  • Estimation of latent ability or proficiency distributions
  • Provision for items inserted in tests to estimate item statistics, but not included in calculation of examinee scores ("variant items")
  • Item fit statistics, theoretical and empirical reliability
  • Information curves and reliabilities for putative test forms
  • Presentation quality IRT graphics, can be imported in Word, Access, etc.
  • Detailed online HELP documentation includes description of interface, syntax, and examples.
 
PARSCALE 4 by Eiji Muraki & Darrell Bock
 
  • The flexibility and the wealth of information provided by this program have kept it in regular use by researchers around the world
  • One, two, and three-parameter logistic models
  • Samejima's model for graded responses
  • Master's partial credit model
  • Generalized partial credit model
  • Analysis of rating scale items such as open-ended essay questions
  • Analysis of multiple-choice items
  • Differential item functioning (DIF)
  • Analysis of mixtures of item types
  • Rater's-effect analysis
  • Multiple-group polytomous item response models
  • Presentation quality IRT graphics, can be imported in Word, Access, etc.
  • Detailed online HELP documentation includes syntax and examples.
 
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