Tetrad is unique in the suite of principled search ("exploration", "discovery") algorithms it provides--for example its ability to search when there may be unobserved confounders of measured variables, to search for models of latent structure, and to search for linear feedback models--and in the ability to calculate predictions of the effects of interventions or experiments based on a model.
Tetrad is a program which creates, simulates data from, estimates, tests, predicts with, and searches for causal and statistical models. It is not intended to replace flexible statistical programming systems such as Matlab, Splus or R.
The aim of the program is to provide sophisticated methods in a friendly interface requiring very little statistical sophistication of the user and no programming knowledge. Tetrad is a Java desktop application that can be installed on any desktop and OS, provided that Java is installed.
Tetrad's causal search algorithms output graphical representations of causal relationships. To ease the analysis of very large graphs with many nodes ('hairballs'), Tetrad has a Cytoscape Plugin which allows you to import the causal graph obtained from Tetrad directly into Cytoscape for visualization and analysis.
If you have Java installed on your computer, clicking the 'install' button on the top of this page, will download the latest JAR file. Opening the JAR file will install and open the application. In case you do not have Java installed; the latest Java version can be obtained here.
The Tetrad codebase is publically available on GitHub. It is released under the GNU GPL v. 2 license and the program may be freely downloaded and used without permission of copyright holders, who reserve the right to alter the program at any time without notification. Executable and Source code for all versions of Tetrad V, and this manual, are copyrighted, 2015, by Clark Glymour, Richard Scheines, Peter Spirtes and Joseph Ramsey.