Story
The F-35 joint strike fighter was conceived in the late 1990s to replace the Air Force’s F-16, the A-10, the Navy’s F/A-18, and the Marine’s Harrier. Now if you’re not familiar with these planes, that’s okay. The point is that the performance requirements for these aircraft are very different and many are in conflict with one another. For example, the optimal design for a high-altitude aircraft where the air is thin has large wings to make turns quickly. Whereas the optimal design for low-altitude aircraft where the air is thick, has small wings, reducing drag and making a small target. Take off and landing from an aircraft carrier requires a rugged and heavy airframe, a lot of extra weight that’s not required by a plane that lands on a runway. And vertical takeoff and landing is a whole thing by itself. It means that being able to take off and land like a helicopter and then fly like a normal jet.
Imagine the increased complexity of piloting such a craft much less a combination of all four crafts. So how is the F-35 fared? The original estimated cost for an F-35 in 2001 was about $70 million per plane. Today, one F-35A, the Air Force’s version, costs $148 million. One F-35B, the Marine Corps version, costs $251 million. And one F-35C, the Navy version, costs a whopping $337 million. And the costs are still rising. The plane is riddled with bugs, performance problems, and usability problems. One critic summarized the situation like this. “The F-35 can’t turn, can’t climb, can’t run. “It is by an objective measure, a failed design.”
Takeaway
The flexibility-usability tradeoff is related to the well-known maxim, jack of all trades, master of none. Flexible designs can perform more functions than specialized designs, but they perform the functions less efficiently. Flexible designs are, by definition, more complex than inflexible designs, and as a result are generally more difficult to use. For example, a Swiss Army Knife has many attached tools that increase its flexibility. These tools taken together are less usable and efficient than corresponding individual tools that are more specialized but provide a flexibility of use not available from any single tool. The flexibility-usability tradeoff exists because accommodating flexibility entails satisfying a larger set of design requirements, which invariably means more compromises and complexity in the design.
It is a common assumption that designs should always be made as flexible as possible. However, flexibility has real costs in terms of complexity, usability, time,and money; it generally pays dividends only when an audience cannot clearly anticipate its future needs. For example, personal computers are flexible devices that are difficult to use, relative to more specialized devices like video game players.However, the primary value of a personal computer is that it addresses uncertainty about how it can and will be used: word processing, tax preparation, email. People purchase video game players to play games, but they purchase personal computers to satisfy a variety of needs, many of which are unknown at the time of purchase.
The ability of an audience to anticipate future uses of a product is a key indicator of how they will value flexibility versus usability in design. When an audience can clearly anticipate its needs, more specialized designs that target those needs will be favored.When an audience cannot clearly define its needs, more flexible designs that enable people to address future contingencies will be favored. The degree to which an audience can or cannot define future needs should correspond to the degree of specialization or flexibility in the design. As an audience comes to understand the range of possible needs that can be satisfied, their needs become better defined and, consequently, the designs need to become more specialized. This shift from flexibility toward specialization over time is a general pattern observed in the evolution of all systems, and should be considered in the life cycle of products.
The flexibility-usability tradeoff has implications for weighing the relative importance of flexibility versus usability in a design. When an audience has a clear understanding of its needs, favor specialized designs that target those needs as efficiently as possible. When an audience has a poor understanding of its needs, favor flexible designs to address the broadest possible set of future applications.When designing multiple generations of products, consider the general shift toward specialization as audience needs become more defined.
Learn More
- LinkedIn Learning
- Page 102 of Universal Principles of Design