Stanford University Stanford Computer Science Department
Abstract    |    Introduction    |    Contacts    |   
   Competing Strategies

   What is PD?
   Political Push
   The Developer

Philosophical Perspective
   Design Philosophy


   Expert Systems Design
   Usability Engeering
   Value Senstive Design

Expert Systems Design

Expert systems, also known as "knowledge-based systems," are a class of computer program that can advise, analyze, categorize, communicate, consult, design, diagnose, explain, explore, forecast, form concepts, identify, interpret, justify, learn, manage, monitor, plan, present, retrieve, schedule, test, and tutor. These types of systems attempt to remove some of the complexity and skill necessary for certain jobs. Typically, an expert system is capable of explaining its reasoning for the decisions it makes and can "learn" as it gains experience. Of course this learning is not like a human learns. Expert systems will instead employ algorithms and store data using the approaches described in any Artificial Intelligence book.

Benefits of Expert Systems

  • Reduced error due to automation of tedious, repetitive or critical tasks
  • Reduced manpower and time required for system testing and data analysis
  • Increased visibility into the state of the managed system

Capabilities of Expert Systems

  • Develop functional system requirements
  • Coordinate software development
  • knowledge acquisition, process analysis, data analysis, system verification Design, develop, and implement an intelligent system


In Scandanavia, the airlines had attempted to design systems that would automate much of the maintenance process for airplanes. Essentially, the expert system would be able to diagnose potential problems with parts of the planes and provide complete and detailed information about the course of action a mechanic should take. Unfortunately, as noted in the film Computers and Context, the mechanics relied on the computer too much. Because the suggestions came from a computer, the workers felt less confident about their own personal evaluations of the situations and tended to place complete trust in the system.

With Participatory Design, the airlines were able to implement a system that augmented the skills necessary for workers to maintain the airplanes, rather than attempting to completely replace the skilled workers. This new system was much better described as a "System for Experts." This is the approach Participatory Design attempts to take in creating systems. In the case of the Scandanavian airlines, it is a better fit than attempting to create systems that replace the skilled workers.

Often system designers fail to take into account the actual users of the programs that are being implemented. There is an attempt by programmers to incorporate too many features or too much functionality in an attempt to make the user more productive. Unfortunately this methodology may make programs more complex and actually decrease productivity as the user attempts to sort out the actual functionality he or she desires. These types of program also tend to not take into consideration the way the users actually work. Participatory Design allows the users to give input into the design process and make it more likely that the finished product will have the functionality required and work as the users envisions.

Ultimately, Expert System Designs are much better suited for situations where there is already a relatively unskilled labor force attempting to do a job. If a system is being built for skilled labor, Participatory Design is much better at helping to extend the capabilities and productivity of a worker. Expert Systems are perfect for sensor validation jobs where many different sensors monitoring conditions or for repetitive jobs that are much better suited for automation. In these types of situations, a computer is better at performing the task. For other tasks, new systems need to enhance the ability people already possess.

Product Development
   Vendor Adoption
   Product Design

In the US
   New Context
   Current Use

   Applied PD

Abstract    |    Introduction    |    Contacts