γ is an inter-coder agreement measure for unitizing a continuum. The measure is fully described in the following paper:
The Unified and Holistic Method Gamma (γ) for Inter-Annotator Agreement Measure and Alignment
Yann Mathet, Antoine Widlöcher, Jean-Philippe Métivier
Computational Linguistics, MIT Press, September 2015, Vol. 41, No. 3: 437-479.
get the PDF here: http://www.mitpressjournals.org/toc/coli/41/3, e-mail to the authors: e-mail.
Gamma Software is a Java implementation of γ which comes with a graphical user interface. It can be run on any system, including Windows, Mac OS X and Linux.