OSCATS Announcements

OSCATS 0.6 Released

2011-11-04T14:51:00.000-05:00

The overdue version 0.6 of OSCATS is now available in source and Windows binaries (32- and 64-bit). New 32- and 64-bit Windows binaries of GSL are also available. While functional, this release should still be considered another in a line of Beta releases leading up to version 1.0. Testers wanted! Send feedback to the mailing list or file an issue for coding errors.

Major changes in this release include:

New OscatsSpace and OscatsPoint classes for a unified representation of continuous, binary, and ordinal latent spaces
Unification of the OscatsContModel and OscatsDiscrModel into a single OscatsModel based on the new latent space representation
Generalization of OscatsItem to allow any arbitrary number of models for complex simulation studies

Other highlights include:

Implementation of the a-Stratified item selection algorithm
Newly implemented models:

Partial Credit, Generalized Partial Credit
Graded Response (Homogenous and Heterogenous Logistic)

New examples, including implementation of a custom algorithm in Python

For a complete list of changes, see the repository commit log.

Plans for upcoming development include:

Support for simultaneous testing of multiple examinees
Exposure control and item selection constraints
R Bindings
Support for GObject Introspection
Example integration with Concerto for CAT administration

Upcoming Developments

2011-08-30T22:04:00.000-05:00

After a hiatus, development on OSCATS is continuing. Below are listed some changes to appear in the Hg repository soon, and the next release is planned for 1-2 months from now.

Also, there are some new (and rather experimental) introspection-based MATLAB bindings for GObject at the gmatlab project. They're ready for general use, but those interested who have some stamina may want to take a look.

GObject-Introspection support for liboscats
Shift language bindings to GO-I methods (perl, python, java)
Unified latent space object for continuous and discrete latent variables
Unified model support, allowing each Administrand to have an arbitrary number of models (for different purposes, e.g. simulation, estimation, calibration, statistical interest)
Support sub-classing models and algorithms in bound languages
More common IRT/CD models
More item selection algorithms, including a-Stratified and Dual-purpose methods
Simpson-Hetter exposure control

OSCATS 0.5 Released

2010-08-24T18:57:00.000-05:00

OSCATS version 0.5 has been released. Source and compiled Windows binary distributions are available, as well as a compiled distribution of GSL 1.14 for Windows.

Note of Upcoming Changes:
The language bindings will be shifting to GObject Introspection-based implementations, where possible, by version 1.0. This will streamline bindings generation even more and make OSCATS potentially available in more programming languages. However, it may entail some changes to function nomenclature.

Welcome to OSCATS!

2010-08-15T15:20:00.000-05:00

A working preliminary version of OSCATS has been loaded into the code repository. Source and Windows binary distributions for version 0.5 will be available shortly (waiting to correct a problem with the Java bindings on Windows).

This initial version includes bindings for Python, Perl, PHP, and Java for use of built-in functions, models, and algorithms. OSCATS can be used from Matlab via the Java bindings. Full bindings for Matlab, as well as support for creating new models and algorithms in bound languages is targeted for version 1.0.

Features:

IRT Models included: 1PL (Rasch), 2PL, 3PL, Nominal response
Classification Models included: DINA, NIDA
Selection Algorithms included:

Random
Optimize an arbitrary criterion
Closest difficulty
Maximize Fisher information
Maximize KL information (for IRT or classification)

Can simulate based on either IRT or classification
Support for examinee covariates in IRT models
Support for tagging item characteristics (e.g. "algebra," "geometry," "negative stem," etc.)