Tetra Single DM and
Group DM Online Help

© Scientific Metrics 2002-2022


Tetra is a tool which implements the Preference Function Modeling methodology for subjective measurement and multi-criteria decision analysis. It is used to assist decision makers in making decisions based on multiple criteria.

Tetra comes in two versions: One of which is used by a single decision maker (SDM). It is 'standalone,' in that everything is installed on a single computer, and all model information is stored in documents on that computer. The other is for group decision making (GDM). It is based on the use of a Tetra server, and all model information is stored on the server, allowing it to be accessed by users running Tetra on multiple workstations on a network.

For the most part, usage of the two versions is identical. The primary differences are in the creation of and access to models. In particular, in the GDM version, only Tetra administrators can create models and make them accessible to users. Creating models for Tetra GDM is done using a separate Administration Tool. The GDM version also includes facilities for managing the decision makers involved. This help information describes the functionality of both versions of Tetra, clearly identifying when the two versions differ.

The process of using Tetra to make a decision consists of seven steps:

  1. Create a model.
  2. Define the decision makers who will be involved in the process (GDM only).
  3. Define the alternatives to be considered in making the decision.
  4. Define the criteria upon which the decision will be based. These criteria may be defined in a tree-like structure, using main criteria, sub-criteria, sub-sub-criteria and so on.
  5. Define the weights for all the criteria. These are defined relatively, specifying how important each criterion is in relation to others. The weights are defined in each node of the criteria tree. In GDM decision maker weights must also be defined.
  6. The decision makers enter their ratings for each alternative with respect to each criterion.
  7. Solve the model that has been created by the previous steps to compute the overall scores and get a numerical rating of the alternatives that corresponds to the combined ratings of all of the decision makers.

This section contains subsections on the Tetra Main Window the Toolbar and the Preferences.