Decision Trees

Decision Trees are about "structuring" contingent decisions.
Decision Tree add-ins enable the construction of a decision tree for visual modeling of contingent decisions in the face of uncertain future outcomes. (Note: Decision trees are a tool from the discipline of “decision analysis”.)

TreePlan by TreePlan
 “TreePlan helps you build a decision tree diagram in an Excel worksheet using dialog boxes. Decision trees are useful for analyzing sequential decision problems under uncertainty. TreePlan automatically includes formulas for summing cash flows to obtain outcome values and for calculating rollback values for determining optimal strategy.”
Decision Tree Software by Vanguard Software Programs
 “Vanguard's decision tree software will help you select the best course of action in cases where you face uncertainty. For example, decision trees are applied in deciding how much inventory to build when sales forecasts are uncertain, or when choosing between litigation and an out-of-court settlement. In helping you to select the best option, Vanguard's decision tree software provides an elegant framework for combining all options involved in a decision with consequence probabilities and outcome values.”

PrecisionTree by Palisade Corporation
PrecisionTree allows you to create decision trees and influence diagrams directly in Excel. PrecisionTree allows users to organize decisions efficiently while considering all possible options and analyzing all available information. Influence diagrams are used to show relationships between events on a general scale, and decision trees (with decision, chance, logic and risk nodes) outline the numerical details of a decision. There is no limit to the size of a tree that can be defined, and trees can span multiple worksheets or multiple workbooks. After an analysis, PrecisionTree creates an easy-to-understand report right in your current workbook that details the best decision to make and the risk associated with that decision. PrecisionTree can also be used with @RISK to perform thorough risk analyses on decision trees.” (Standard and Professional versions)

Risk Solver Platform by Frontline Systems
"New in Risk Solver Platform is a facility to create decision trees on your Excel spreadsheet.  Using the Ribbon, you can easily create decision nodes and branches, event nodes and branches, and terminal nodes.  The tree is drawn in graphic form on the spreadsheet; standard Excel worksheet formulas compute 'rollback values' at each node, and the best-choice value at the root node, based on either expected value or utility function (certainty equivalent) criteria.  With a Ribbon choice, you can graphically highlight the optimal path through the tree."

XLTree Commercial Edition Decision - Trees with 99 branches per node.

Risk Detective by Rhythm Technology, Inc.
Risk Detective works entirely within Excel in an easy to use and simple to learn way to provide decision analysis capability for all your business situations.”

Lumenaut Decision Tree by Lumenaut
 “The Lumenaut Decision Tree package provides a range of tools that enable the user to easily and quickly build decision tree models for many real life situations natively in Excel. The user can quickly model real life decision processes in Excel and select the decision path that produces either the highest or lowest outcome. By making better informed decisions, companies can select the optimum path for their business.”