Tetrad is a software suite for simulating, estimating, and searching for graphical causal models of statistical data.

The Tetrad suite can be used from the command line or with a graphical user interface, either natively or via a Python program, Py-Tetrad, or via R with Rpy-Tetrad. Tetrad contains more than 20 theoretically reliable, well-tested search algorithms for a variety of data settings, including searches for causal models with unmeasured confounders. Tetrad has facilities for model simulation, parameter estimation, assessment, and comparison. The software allows users to guide search procedures with prior knowledge.

It is a free tool with a 35-year history of algorithms developed by dozens of philosophers, computer scientists, and statisticians.