Shared Vision Models

Object-Oriented Simulation Software

At the heart of the concept of shared vision modeling is the use of the appropriate computer simulation software. The genre of computer simulation software that is used for shared vision modeling is “object-oriented simulation software.” Palmer, Keyes and Fisher (1993) describe how “object oriented simulation environments are not based on traditional procedural coding such as in FORTRAN, but rather are based upon the graphical manipulation of objects or 'icons' that have specific characteristics and can perform specific functions.” This idea of object-oriented simulation is key to providing a simulation environment where all stakeholders can collaboratively build and trust the model. General characteristics of object-oriented simulation software that make it compatible with the concept of shared vision modeling are:

1. The relationships are represented by graphical illustrations versus complicated code.
2. Mathematical relationships are transparent so there is no "black box."

Graphical illustrations are important because this provides a user-friendly environment for the stakeholders to interact.  Transparent mathematical relationships are also crucial for facilitating trust in the model by stakeholders.

There are several packages of software that can be used for shared vision modeling, and as time goes by more and more software package will become available to try.  STELLA® (High Performance Systems, Inc) is a software package that has been used extensively for shared vision models in Shared Vision Planning processes by the Corps and Dr. Richard Palmer. Other software packages that have been used for shared vision models include PowerSim® (Powersim Software, Inc.) and MS Excel®.  (This is by no means meant to represent a comprehensive list of software capable of meeting the needs of shared vision modeling).  

During the National Drought Study, the Corps of Engineers found that the object-oriented simulation environment (specifically in STELLA®) showed the ability to empower those not normally involved in the modeling process in the following ways:   

1. Non-programmers recognized their ability to directly impact the modeling process.
2. Stakeholders found that the model provided previously unavailable information, which resulted in a better understanding of the planning and management options available. Stakeholders were better able to recognize the interactions in the system and to appreciate the overall management of the system.
3. Stakeholders discovered they could use the models to evaluate alternatives and options without the delays often associated with computer models.
4. Stakeholders found they had confidence in the output of the models because they had been intimately involved in the modeling process from start to finish.

In order to help solidify the concepts of shared vision modeling using object-oriented software packages discussed thus far, the following links provide illustrations of shared vision model interfaces.

• A simple step-by-step demonstration of how to model in the object-oriented environment using a hypothetical case where a town decides it needs to meet its water demand by withdrawing water from the local river.
• System diagram for the shared vision model for the Rappahannock River Basin in Virginia water supply shared vision planning effort.
• Examples of user interactive interfaces (ppt, 2.9 MB) developed by Dr. Richard Palmer.

Reviewed 13 Feb 2009