Products & Services

We offer the only software packages and custom software for evaluation, measurement and decision making that are based on sound mathematical foundations. We also provide consulting services and training in the use of this software.

The Importance of Sound Mathematical Foundations

Without proper mathematical foundations, the numbers produced by competing products are meaningless. The problem of mathematical foundations is difficult and classical decision and measurement theories are founded on errors. Among other things, the elementary operations of addition and multiplication are not applicable to scale values that are constructed by any of these theories. For details see our Publications and Presentations pages.

Preference Function Modeling &

We have developed a new theory of proper measurement and, based on this theory, a new practical methodology named Preference Function Modeling (PFM).1 Tetra, our software implementation of PFM, has features unlike any competing product. In addition to its sound mathematical foundations, its user interface includes innovations that make it easy to learn. The multi-user version is the only available true Group Decision Making software with proper mathematical foundations.

PFM is a methodology for multi-criteria and multi-user evaluation, decision making and subjective measurement. It constructs a mathematical model (preference function) of the Decision Maker’s preferences. PFM handles weights and relative importance correctly to enable Decision Makers to measure the performance of alternatives under conflicting criteria and it produces preference measurement scales that enable addition, multiplication, order and the application of calculus. Tetra is a faithful implementation of PFM.

For information on purchasing Tetra, or to download the free demo, please visit our Try & Buy page.

1 For details on PFM, see our Publications and Presentations pages.



NEW: Spectral Algorithm

NEW: Linear Equations Challenge

Supply and Demand Equilibrium and Debreu’s Theory of Value

Economic Theory’s Curves

Demand, Barter, and Exchange

And the Math is Incorrect

The Foundations

Decision Theory

Utility Theory


Download Tetra

Tetra Quickstart Guide

Tetra Online Documentation




An Elementary Demand Theory Error

Ordinal Utility and Indifference Curves

Von Neumann's Error

Game Theory: Whose Values?