A Balanced Model for Product Usability


December 2004

A Balanced Model for Product Usability

CIDMIconNewsletter Charlie Dowdell, Manager of Technical Publications, The Raymond Corporation

This article introduces a new model for consideration in the development of information systems: the Balanced Model for Product Usability. This model serves as a practical guide for design usability assessment. One of the strengths of the model is that it illustrates the integration of previously diverse disciplines. All of the elements of usability regarding the overall design of the product are taken into account.

There is a constant stream of new models to help communicators of information increase their understanding of what constitutes usability and their ability to provide information that maximizes the usability of a product. In the Random House College Dictionary, the word usable is defined as “convenient and capable of being used.” Usability is used to describe the ease of interaction between human and machine. The Balanced Model strives to illustrate the relationship between hardware, including computers and computer programs, and information that maximizes the usability of a product. This model looks at the relationship between hardware, software, and what I call infoware; information that instructs about the use of a product. (See Figure 1.)


Figure 1. The Balanced Model of Product Usability

The information science is full of models and unprovable theories that have done little to achieve an understanding of how to move to higher usability levels. Recently, the Information Architecture community has entertained numerous models using Venn Diagrams. The Venn Diagram is an excellent choice for describing logical models and aids in the understanding of relationships. A popular model using the Venn Diagram is the Louis Rosenfield Information Architecture Areas of Practice model. Venn Diagrams were introduced in 1880 by John Venn, MA Fellow and Lecturer in Moral Science, Caius College, Cambridge University.

The Balanced Model of Product Usability

To understand the Balanced Model, boundaries around the labels of hardware, software, and infoware must be defined. Hardware and software use highly structured information that we usually refer to as data. Infoware is generally created in natural language to be understood by humans.

  • Hardware-Infrastructure or substrate for information or data
  • Software-Machine-understandable data
  • Infoware-Human-understandable information

Hardware is traditionally defined as a tool or metalwork differentiated from the theory and design of the item. We can say, for this model, that hardware is a physical repository or substrate for data. All products must contain some form of hardware because information cannot exist without a physical repository. Even information in a human has the physical mind as its repository. Information in the newspaper is stored as type. Information in a computer is stored as RAM.

Software is the logical representation of data. In the balanced model, software includes only machine-understandable data. Software may contain and manipulate natural language information, but it cannot interpret it in the way humans can. In a way, Extensible Markup Language (XML) is a bridge between machine-readable data and natural language information. Software can manipulate XML and act on its syntax. Ultimately, XML must be converted to natural lanuguage through HTML and a browser to make it fully understandable. With proper tools, XML can be both information and data at the same time.

Infoware is information in natural language that is understandable by humans, contrasted with software that is machine-understandable. Infoware may be instructions coded into a GUI, a procedure manual, or the brain understanding that when a mouse is clicked, a reaction occurs. Interestingly, infoware and software find a common ground through the programmer. The programmer can understand how the machine will behave when the software is run.

Product usability
To obtain maximum usability for a product, the Balanced Model requires that all three “wares,” hardware, software, and infoware, must be considered equally during product design. If any one or two of these “wares” are emphasized without consideration of the others, the product will not be balanced and will not achieve maximun usability. This interconnectedness can be demonstrated using the Venn Diagram in Figure 2.

The diagram uses three interconnected circles to represent hardware, software, and infoware. The intersections create seven regions that I have labeled S, SH, H, SI, SHI, IH, and I. A product in development may reside in one of these seven regions.


Figure 2. The Balanced Model of Product Usability with Intersections

We can immediately eliminate regions S, SI, and I from further consideration because we have already indicated that neither software nor infoware can exist without hardware. Thus, a product can exist in one of four regions. Examples of products are

    • SH-Embedded processors in cars and lift trucks. Embedded processors in appliances, radios, TVs, or ovens
    • SHI-Standard computer applications. MS Word
    • IH-Products without processors that still must have documentation or training. Espresso makers
    • H-Hardware products with obvious uses. Windows, floors, roofs

Let’s walk through some examples to further understand the model.

Example 1. Basic Computer Architecture
Remember your DOS computer in the days when we had shell after shell of WYSIWIG and applications running? In this case, the definition of hardware is relatively simple. It is the circuit board, the support chips, and the other physical apparatuses that facilitate the execution of voltage level “words” to perform complex functions.


Figure 3. Basic Computer Example of Product Usability

The software is, of course, the binary picture that allows the microprocessor (hardware) to become useful. The software is of no tool-value without compatible hardware and, of course, the hardware is of no tool-value without compatible software. It is interesting to consider that the term “computer architecture” was coined to refer to the convergence of hardware and software. In those days, the information in the designers head was not considered part of the systems thinking that could help us move ahead in computer and information sciences.

The additional element of a user manual or information resource (or brain-resident knowledge) is as important as the two previous definitions. Tool-value only manifests itself if the information exists to run and apply the tool-value of the hardware/software combination. Consider a circumstance in which the software/hardware combination is running, just counting up, counting down, or running a more complex algorithm. In this circumstance, there is no tool-value since the mission, or application, has not been defined by the infoware.

The model, once understood, can be effectively applied to tools other than basic computer applications.

Example 2. A Door Knob and Door Latch Mechanism
The knob, interface, and visual cues regarding how the hand is applied to a door knob is infoware. The mechanics of the physical manifestation of the hardware is, of course, hardware in the true sense of the word hardware. The information (design) applied to the metal and mechanism to provide the leverage necessary and the clearances to allow the mechanism to function is “software.” The software is information that is machine readable. For example, we do not know the exact dimensions of the plunger on the door latch; however, the dimensions are necessary to dictate the functions that are present. The parts cannot be too loose or too tight. The pieces need to “communicate” and “read” each other to function correctly. No human readable information is required in this case. The user neither knows nor understands that the dimensions are correct. Only in the event of a troubleshooting effort or original design work would the user delve into the technical aspects of machine understandable information or software.


Figure 4. Door Knob Example of Product Usability

As part of your next information project, consider the balanced model. Test your assumptions of the burdens of hardware, software, and infoware as part of your overall design review practice. Make a three-column list, with headings of hardware, software, and infoware. Place the items you are working with in each of the columns. Ask yourself if there is a bias toward one column. Consider which of these columns is not in good balance with the other columns in the development effort.

Information project success will come with a good understanding of the concepts in this model. Practical applications of the concepts to a particular project will yield better decisions and help direct efforts towards a balanced system, thus maximizing tool-value. CIDMIconNewsletter

About the Author

Dowdel photo b-w20

Venn Diagrams were introduced in 1880 by John Venn, “M.A. Fellow and Lecturer in Moral Science, Caius College, Cambridge University”, in a paper entitled On the Diagrammatic and Mechanical Representation of Propositions and Reasonings which appeared in the Philosophical Magazine and Journal of Science S. 5. Vol. 9. No. 59. July 1880.