Thursday, April 9, 2015

Manipulator v1.2

 The third free IRT tool from is the Manipulator. This spreadsheet was originally designed to be used in the half-day pre-conference training that we will deliver in the NCME 2015 Conference with Prof. David J. Weiss of the University of Minnesota. Enjoy!!! Click here for more information.

                                                              Alper Sahin, Ph.D.

Monday, June 2, 2014

Test Form Building Assistant (TFBA)

I am happy to inform you that another free IRT tool, Test Form Building Assistant (TFBA), is ready for download.  Click here for more information

P.S. : In order to benefit from all features, you need MS Excel 2007 and above.

Wednesday, December 4, 2013

Free irt tools

The first free irt tool from has been released. It is an excel spreadsheet prepared to let researchers and students easily observe the change in item response functions (IRF), item information functions (IIF) and the hypothetical Standard Error (SE) values attributed to these IIFs with the change in the item parameters. The program is based on 3 Parameter Logistic Model (3PLM). However, similar IRFs and IIFs in 2 Parameter Logistic Model (2PLM) can be obtained if "c" parameter is set to "0". Accordingly, if "a" parameter is fixed to "1" and "c" is fixed to "0", IRFs and IIFs similar to 1 Parameter Logistic Model (1PLM) can be obtained. For more information about the program and some screenshots, please click here.

Tuesday, December 3, 2013


Welcome to If you are reading this post, it means that you are a person who is interested in Item Response Theory (IRT). If this is the case, you are at the right place. aims to make IRT more common among the language testing professionals, educators and educational researchers. In order to reach this aim, will provide the IRT practitioners with some free IRT tools and will try to be a meeting area for the IRT practitioners all over the world. So, you will be able to find some tools, news items and articles which will make you understand IRT. If you have any inquiries feel free to contact me from

Alper SAHIN, ph.D.