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Supertree and Sensitivity

Decision Analysis Software

Decision analysis is a comprehensive process for making sound decisions in the face of uncertainty. Sensitivity and Supertree are powerful software packages designed to help decision analysts make the most of the decision analysis process. Sensitivity identifies critical uncertain inputs to spreadsheet decision models, and Supertree analyzes decision trees, taking into account the critical uncertainties. In combination with spreadsheet models, these programs automate the decision analysis process, helping the analyst to generate insights that lead to better decisions.

Sensitivity

Sensitivity analysis identifies the uncertainties that are most important to consider when making a decision. The analysis starts by constructing a spreadsheet model to compute the consequences (e.g., profit) associated with each decision alternative. Typically, the model has several uncertain input variables.

Sensitivity determines which of these uncertain inputs are major contributors to the risk associated with each decision alternative. It does this by replacing baseline values for each variable in the spreadsheet model with high and low values and then calculating the resulting “swing” in model outputs. Results are displayed graphically as a “tornado diagram” (see illustration) or in numerical form. These critical uncertainties are then analyzed using the Supertree program.

Special features

Links with Microsoft Excel and other spreadsheet programs
Links with Powersim Constructor, a system dynamics program
Evaluates single and joint sensitivities (simultaneous changes in two or more dependent variables)
Allows user to import data from an input table (like Risk Detective—a feature for Excel spreadsheets only)
Evaluates sensitivities for more than one output variable
Plots “tornado diagrams”

Supertree

Developed by the founders of decision analysis, Supertree is one of the most widely used professional decision analysis computer programs. The program evaluates decision trees, determines the risk associated with any decision alternative in the tree, and identifies the best alternative for decision makers. Using prompts and easy-to-understand input screens, the program guides the construction, evaluation, and analysis of decision tree models.

Supertree provides a powerful set of tools to portray uncertainty graphically, perform sensitivity analyses, and obtain the value of information and of control.

Special Features

Links with Microsoft Excel and other spreadsheet programs
Links with Powersim Constructor, a system dynamics program
Handles large decision trees. Has options to display schematic and full tree structure
Calculates expected values, expected utilities and determines the optimal decision based on a specified risk attitude
Automatically re-orders tree nodes to calculate values of information and control
Calculates and plots sensitivities to probabilities and attitude toward risk
Displays probability distributions in histogram, cumulative, “flying bar,” and tabular form
Computes results for multiple output variables (e.g., impact on NPV and manufacturing costs)

Sensitivity

Command Structure

Sensitivity’s command structure is easy to follow (see Tutorial tab). Common menu items can also be selected from a convenient toolbar located just under the menu.

Sensitivity interfaces with spreadsheet financial models and with models written in APL or Basic programming languages. (It is not necessary to know programming to use Sensitivity).

Entering variable data is easy. Sensitivity prompts you to enter low, base, and high values for each variable. After all data has been entered, the Show Sensitivity Data command creates a summary of the inputs. The screen display to the right, for instance, shows a model for a new product with 11 variables. Variables can be easily changed and updated.

Following data entry, Sensitivity links with your spreadsheet and runs the model, inserting base, low, and high values for each variable and recording the swing in results. The results are displayed in a graphic form with the variables ordered relative to the sensitivity of the model results, producing a “tornado diagram.” In the example, Price, Peak Market Share, Unit Cost, and Years: Start to Decline, would be chosen for probabilistic evaluation using Supertree.

Supertree

The Supertree command structure is similar to Sensitivity (see Tutorial tab). Common menu items can also be selected from a convenient toolbar located just under the menu.

The ability to manipulate, change, reorder, and perform probabilistic and risk attitude sensitivity tests makes Supertree an extremely powerful analytic tool. Like Sensitivity, Supertree is most often linked to spreadsheet models to calculate tree values.

The display shows a sample decision tree prepared for Supertree input. Most nodes need to be entered only one time. Dependent nodes (probability, outcome, or both) are handled easily, without the need for duplicating entries.

After entry, the model can be displayed in decision tree, schematic tree, or a condensed tabular form for easy review of large trees.

A myriad of analyses can be performed with Supertree. Distributions can be plotted in histogram or cumulative probability form. Results are available in tabular form and can be exported into other graphics software packages. Single or multiple plots can be made at any node, combination of nodes, or for the entire tree.

Supertree also displays the sensitivity of the model to probabilities and risk attitude.

Tutorial

The following files are excerpts from the User’s Guide for Supertree and Sensitivity. Click on the file name to view it in the browser. To view these files, you will need to have Adobe Acrobat installed on your computer.

Some of these files are large and may take a long time to download and view. Once the file is downloaded, you can save the file to your hard disk by clicking the image of a disk on the Acrobat toolbar. To download the file without viewing, right-click on the name and choose Save Target As….

Tutorials

Sensitivity Example (856 k)
Sensitivity Advanced Topics (891 k)
Supertree Example (1,132 k)
Supertree Advanced Topics (2,009 k)

These tutorials use a case describing a new product introduction case for Sensitivity and a bidding situation for Supertree. To assist you in following the tutorials, the Sensitivity/Supertree installer has put a copy of the Excel workbooks newprod.xls and bidding.xls and the Sensitivity file newprod.asn in the installation folder, c:\super95.

Using Supertree and Sensitivity With the Fourth Edition of Decision Analysis For the Professional

Using Supertree with Decision Analysis for the Professional (696 k)
Excel workbook for Chapter 6 (45 k)
Sensitivity Files for Chapter 6: Static New, RF Plus, Milk
Supertree Files for Chapter 6: Figure A-34, Figure A-35, Figure A-36, Figure A-37 (figures in the Using Supertree With Decision Analysis for the Professional file above)
Errata in Decision Analysis for the Professional, Third Edition(22 k)

FAQ

This page contains answers to common questions handled by our support staff, along with some tips and tricks that we have found useful. More information can be found in the Help menu of Supertree and Sensitivity.

Installation

What are the system requirements?
The minimum hardware requirements are:

Windows 95, 98, 2000, NT, XP, Vista, 7, 8, or 10
8 megabytes of RAM
3 megabytes of free space on the hard disk

When installing the program, it is best to follow the installer’s suggestion and install Sensitivity and Supertree on the c: drive and in a folder called c:\super95.

How do I start the programs
Go to the Start menu at the bottom of the Windows screen, choose Programs and the folder Supertree 95 and select the Supertree or Sensitivity icon.

To create an icon to start the programs on the desktop (or elsewhere), choose Programs from the Start menu and double-click on the Supertree 95 entry to open the folder. Select the Sensitivity icon and choose Copy from the Edit menu. Go to the location in which you want to place the icon and Paste. Repeat for the Supertree icon.

How can I uninstall Supertree and Sensitivity from my computer?
If for some reason you wish to remove Supertree and Sensitivity from your computer, use the Add or Remove Programs function from the Control Panle of your computer. If you have an older version of Supertree, you may need to use the following procedure:

Open Windows Explorer
Select the super95 folder in HD(C:).
Choose Delete from the File menu.
Open the \Windows\Start Menu\Programs folder, select the Supertree 95 folder, and choose Delete from the File menu.

Troubleshooting

Where can I find some tips on using the programs?
Some tips on the use of the programs can be found in the file “Tips and Troubleshooting” in the Tutorials section of this website.

How can I troubleshoot problems?
The best way to troubleshoot problems with the programs is to consult the Help menu in the programs.

Some troubleshooting hints can be found in the file “Tips and Troubleshooting” in the Tutorials section of this website.

What about that Excel error “macro error at cell A4”?
When Supertree or Sensitivity interfaces with an Excel workbook, it writes a set of instructions in a macro called supermac.txt. When a macro error occurs it is almost always because one of the node names (Supertree) or variable names (Sensitivity) does not correspond to a range name in the workbook. The macro error can also occur if the result name for the endpoint node (Supertree) or model (Sensitivity) does not correspond to a range name in the workbook.

When the macro error occurs, Excel remains open and you can troubleshoot the problem immediately.

Switch to Excel and to the supermac.txt window.
Click on the cell A4 (or whatever whatever cell the error message indicates.)
From the Tools menu, choose Macros from the Macro option, and click the Step Into button. A dialog box will show you the complete contents of the cell.
Click the Evaluate button repeatedly until you see the error occur. This will identify the mistaken entry for a range name.

Why does Excel say that “this workbook contains a type of macro that cannot be disabled?”
Microsoft has recently created safeguards against malicious code appearing in the form of macros that are attached to documents or spreadsheets. Supertree and Sensitivity interface with Excel using a macro, and the message reflects a conflict between the programs and the security settings. The solution to this problem can be found in a file in the tutorial section.

Why could a non-English language version of Excel open the file “supermacro.txt” but not run it as a macro?
When Supertree or Sensitivity interfaces with an Excel workbook, it writes a set of instructions in a file called supermac.txt. This file contains a set of instructions which are run as a macro.

Microsoft Excel is apparently not consistent in how it determines the separator (usually a comma, but in some regions a semi-colon) used in macros. If the macro does not run at all, try changing the List Separator entry to a comma (,) in the Regional Setting Control Panel of Windows.

For further information, see the file linked to “Problems with non-English language versions of Excel and Windows” in the tutorial section.

Versions

Supertree and Sensitivity upgrades usually add a feature or correct a minor problem with some hardware, software, or operating system.

This page records the changes for versions after 10.33

Version 10.34

Corrects a problem displaying negative numbers when Supertree and Sensitivity run under the Chinese language version of Windows. Choose Set Options from the Supertree and Sensitivity File menus to select the “short” negative sign to avoid problems with the two-byte Chinese character set.
Corrects a problem in which Supertree and Sensitivity would not print to certain printers under the Windows NT and Windows 2000 operating systems.
Allows 10 or more distributions to be plotted as 10/50/90 bars without overlapping.

Version 10.35

If there are multiple value measures, Supertree and Sensitivity now offer an option to use the Excel range name of the value displayed as the value axis label in plots.
Corrects a problem with running macros during a Supertree or Sensitivity evaluation. Sometimes Excel could not find the macro.
Creates more user friendly error messages for certain “input data missing” situations.

Version 10.36

An error was caused by a new feature in 10.35: The RecallDistribution option of the File menu would not work for certain plots.

Version 10.37

Makes the value axis label in RecallDistribution option of the File menu independent of the choice in other plots (see new feature in version 10.35).
Detects repeated node numbers in dependency list for Supertree endpoint nodes.

Version 10.38

Version 10.38 is a maintenance upgrade and provides the same functionality as version 10.37.
There have been reports of difficulty in using the installer for version 10.38 on non-English systems, and for this reason version 10.37 is also available for download.

Version 10.39

Version 10.39 corrects a problem in one of the Supertree dialog boxes for Analyze/Display Tree when using the Enter key rather than the Tab key to move between entry fields.
A new installer is used for Supertree and Sensitivity. When installing a new version of Supertree, you may be required to use the Control Panel to remove a previous version; this action will remove only the files created by the original installation, not any data files you have created.
The new installer should avoid problems sometimes encountered in installations on non-English systems.

Version 10.40

Version 10.40 corrects a problem that occurs in the following situation: Display Tree and Sensitivity to Probability sometimes showed incorrect results when the following three conditions were true: Different outcome measures were used for the decision criterion and for the display value, and the tree was reordered, and the reordered nodes contain an asymmetric (not all successor nodes the same) decision node.
A new feature has been added to the Options choice in the File menu. This feature allows the expert user to skip warning messages that a “variable may not be available” to the endpoint during the evaluation. These error messages often occur during the evaluation of asymmetric trees when a common Excel endpoint is called from different places in the tree.

Version 10.41

Version 10.41 corrects a problem with the installer program for Version 10.40. The installer no longer requires you to uninstall the previous version.

About Us

Supertree® and Sensitivity® have supported professional decision analysts for more than 30 years.

During these decades the programs have continuously evolved and today bear little resemblance to the early APL models written by SRI International consultants and analysts in the 1970s on mainframes—except in their basic functionality.

Supertree and Sensitivity moved from SRI in the early 1980s to SDG along with many members of the original decision analysis organization. For a brief period, SDG became part of a large consulting organization known as Navigant Consulting but spun off from that organization in the latter part of 2000 to concentrate on its historic strength, strategic management consulting.

At the same time, SDG’s software and systems activities—including Supertree and Sensitivity—were spun off to a separate company, SmartOrg, Inc., founded by decision analysis leaders.

SmartOrg delivers decision systems and solutions that help management create extraordinary value by implementing practices, processes and tools developed and proven at SDG.

For additional information about SmartOrg visit Smartorg.com.

Supertree and Sensitivity are trademarks of SmartOrg, Inc. All other products mentioned are registered trademarks or trademarks of their respective companies.

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