Iterative design
Encyclopedia
Iterative design is a design
methodology based on a cyclic process of prototyping, testing, analyzing, and refining a product or process. Based on the results of testing the most recent iteration of a design, changes and refinements are made. This process is intended to ultimately improve the quality and functionality of a design. In iterative design, interaction with the designed system is used as a form of research for informing and evolving a project, as successive versions, or iterations of a design are implemented.
process. However, changes are easiest and less expensive to implement in the earliest stages of development. The first step in the iterative design process is to develop a prototype
. The prototype should be evaluated by a focus group
or a group not associated with the product in order to deliver non-biased opinions. Information from the focus group should be synthesized and incorporated into the next iteration of the design. The process should be repeated until user issues have been reduced to an acceptable level.
The typical steps of iterative design in user interfaces are as follows:
Iterative design in user interfaces can be implemented in many ways. One common method of using iterative design in computer software is software testing
. While this includes testing the product for functionality outside of the user interface, important feedback on the interface can be gained from subject testing early versions of a program. This allows software companies to release a better quality product to the public, and prevents the need of product modification following its release.
Iterative design in online(website) interfaces is a more continuous process, as website modification, after it has been released to the user, is far more viable than in software design. Often websites use their users as test subjects for interface design, making modifications based on recommendations from visitors to their sites.
that must perform a certain task, and must ultimately fit in a small space on a circuit board. It is useful to split these independent tasks into two smaller and simpler tasks, the functionality task, and the space and weight task. A breadboard
is a useful way of implementing the electronic circuit on an interim basis, without having to worry about space and weight.
Once the circuit works, improvements or incremental changes may be applied to the breadboard to increase or improve functionality over the original design. When the design is finalized, one can set about designing a proper circuit board meeting the space and weight criteria. Compacting the circuit on the circuit board requires that the wires and components be juggled around without changing their electrical characteristics. This juggling follows simpler rules than the design of the circuit itself, and is often automated
. As far as possible off the shelf
components are used, but where necessary for space or performance reasons, custom made components may be developed.
Several instances of iterative design are as follows:
Other benefits to iterative design include:
Observation and studies of participants show that kindergartners are regularly able to build higher structures, in comparison to groups of business school graduates. This is explained by the tendency for children to at once stick the marshmallow on top of a simple structure, test the prototype, and continue to improve upon it. Whereas, business school students tend to spend time vying for power, planning, and finally producing a structure to which the marshmallow is added. The challenge was invented by Peter Skillman of Palm, Inc.
and popularized by Tom Wujec of Autodesk
.
Design
Design as a noun informally refers to a plan or convention for the construction of an object or a system while “to design” refers to making this plan...
methodology based on a cyclic process of prototyping, testing, analyzing, and refining a product or process. Based on the results of testing the most recent iteration of a design, changes and refinements are made. This process is intended to ultimately improve the quality and functionality of a design. In iterative design, interaction with the designed system is used as a form of research for informing and evolving a project, as successive versions, or iterations of a design are implemented.
Iterative design process
The iterative design process may be applied throughout the new product developmentNew product development
In business and engineering, new product development is the term used to describe the complete process of bringing a new product to market. A product is a set of benefits offered for exchange and can be tangible or intangible...
process. However, changes are easiest and less expensive to implement in the earliest stages of development. The first step in the iterative design process is to develop a prototype
Prototype
A prototype is an early sample or model built to test a concept or process or to act as a thing to be replicated or learned from.The word prototype derives from the Greek πρωτότυπον , "primitive form", neutral of πρωτότυπος , "original, primitive", from πρῶτος , "first" and τύπος ,...
. The prototype should be evaluated by a focus group
Focus group
A focus group is a form of qualitative research in which a group of people are asked about their perceptions, opinions, beliefs and attitudes towards a product, service, concept, advertisement, idea, or packaging...
or a group not associated with the product in order to deliver non-biased opinions. Information from the focus group should be synthesized and incorporated into the next iteration of the design. The process should be repeated until user issues have been reduced to an acceptable level.
Application: Human computer interfaces
Iterative design is commonly used in the development of human computer interfaces. This allows designers to identify any usability issues that may arise in the user interface before it is put into wide use. Even the best usability experts cannot design perfect user interfaces in a single attempt, so a usability engineering lifecycle should be built around the concept of iteration.The typical steps of iterative design in user interfaces are as follows:
- Complete an initial interface design
- Present the design to several test users
- Note any problems had by the test user
- Refine interface to account for/fix the problems
- Repeat steps 2-4 until user interface problems are resolved
Iterative design in user interfaces can be implemented in many ways. One common method of using iterative design in computer software is software testing
Software testing
Software testing is an investigation conducted to provide stakeholders with information about the quality of the product or service under test. Software testing can also provide an objective, independent view of the software to allow the business to appreciate and understand the risks of software...
. While this includes testing the product for functionality outside of the user interface, important feedback on the interface can be gained from subject testing early versions of a program. This allows software companies to release a better quality product to the public, and prevents the need of product modification following its release.
Iterative design in online(website) interfaces is a more continuous process, as website modification, after it has been released to the user, is far more viable than in software design. Often websites use their users as test subjects for interface design, making modifications based on recommendations from visitors to their sites.
Iterative design use
Iterative design is a way of confronting the reality of unpredictable user needs and behaviors that can lead to sweeping and fundamental changes in a design. User testing will often show that even carefully evaluated ideas will be inadequate when confronted with a user test. Thus, it is important that the flexibility of the iterative design’s implementation approach extends as far into the system as it is able to. Designers must further recognize that user testing results may suggest radical change that requires the designers to be prepared to completely abandon old ideas in favor of new ideas that are more equipped to suit user needs. Iterative design applies in many fields, from making knives to rockets. As an example consider the design of an electronic circuitElectronic circuit
An electronic circuit is composed of individual electronic components, such as resistors, transistors, capacitors, inductors and diodes, connected by conductive wires or traces through which electric current can flow...
that must perform a certain task, and must ultimately fit in a small space on a circuit board. It is useful to split these independent tasks into two smaller and simpler tasks, the functionality task, and the space and weight task. A breadboard
Breadboard
A breadboard is a construction base for prototyping of electronics. The term is commonly used to refer to solderless breadboard ....
is a useful way of implementing the electronic circuit on an interim basis, without having to worry about space and weight.
Once the circuit works, improvements or incremental changes may be applied to the breadboard to increase or improve functionality over the original design. When the design is finalized, one can set about designing a proper circuit board meeting the space and weight criteria. Compacting the circuit on the circuit board requires that the wires and components be juggled around without changing their electrical characteristics. This juggling follows simpler rules than the design of the circuit itself, and is often automated
Place and route
Place and route is a stage in the design of printed circuit boards, integrated circuits, and field-programmable gate arrays. As implied by the name, it is composed of two steps, placement and routing. The first step, placement, involves deciding where to place all electronic components, circuitry,...
. As far as possible off the shelf
Commercial off-the-shelf
In the United States, Commercially available Off-The-Shelf is a Federal Acquisition Regulation term defining a nondevelopmental item of supply that is both commercial and sold in substantial quantities in the commercial marketplace, and that can be procured or utilized under government contract...
components are used, but where necessary for space or performance reasons, custom made components may be developed.
Several instances of iterative design are as follows:
- Wiki - A wikiWikiA wiki is a website that allows the creation and editing of any number of interlinked web pages via a web browser using a simplified markup language or a WYSIWYG text editor. Wikis are typically powered by wiki software and are often used collaboratively by multiple users. Examples include...
is a natural repository for iterative design. The 'Page History' facility allows tracking back to prior versions. Modifications are mostly incremental, and leave substantial parts of the text unchanged.
- Common law - The principle of legal precedent builds on past experience. This makes law a form of iterative design where there should be a clear audit trailAudit trailAudit trail is a sequence of steps supported by proof documenting the real processing of a transaction flow through an organization, a process or a system.....
of the development of legal thought.
- Evolution - There is a parallel between iterative and the theory of Natural SelectionNatural selectionNatural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....
. Both involve a trial and error process in which the most suitable design advances to the next generation, while less suitable designs perish by the wayside. Subsequent versions of a product should also get progressively better as its producers learn what works and what doesn't in a process of refinement and continuous improvement.
Benefits
When properly applied, iterative design will ensure a product or process is the best solution possible. When applied early in the development stage, significant cost savings are possible.Other benefits to iterative design include:
- Serious misunderstandings are made evident early in the lifecycle, when it's possible to react to them.
- It enables and encourages user feedback, so as to elicit the system's real requirements.
- The development team is forced to focus on those issues that are most critical to the project, and team members are shielded from those issues that distract them from the project's real risks.
- Continuous, iterative testing enables an objective assessment of the project's status.
- Inconsistencies among requirements, designs, and implementations are detected early.
- The workload of the team, especially the testing team, is spread out more evenly throughout the lifecycle.
- This approach enables the team to leverage lessons learned, and therefore to continuously improve the process.
- Stakeholders in the project can be given concrete evidence of the project's status throughout the lifecycle.
Marshmallow Challenge
The Marshmallow Challenge is an instructive design challenge. It involves the task of constructing the highest possible free-standing structure with a marshmallow on top. The structure must be completed within 18-minutes using only 20 sticks of spaghetti, one yard of tape, and one yard of string.Observation and studies of participants show that kindergartners are regularly able to build higher structures, in comparison to groups of business school graduates. This is explained by the tendency for children to at once stick the marshmallow on top of a simple structure, test the prototype, and continue to improve upon it. Whereas, business school students tend to spend time vying for power, planning, and finally producing a structure to which the marshmallow is added. The challenge was invented by Peter Skillman of Palm, Inc.
Palm, Inc.
Palm, Inc., was a smartphone manufacturer headquartered in Sunnyvale, California, that was responsible for products such as the Pre and Pixi as well as the Treo and Centro smartphones. Previous product lines include the PalmPilot, Palm III, Palm V, Palm VII, Zire and Tungsten. While their older...
and popularized by Tom Wujec of Autodesk
Autodesk
Autodesk, Inc. is an American multinational corporation that focuses on 3D design software for use in the architecture, engineering, construction, manufacturing, media and entertainment industries. The company was founded in 1982 by John Walker, a coauthor of the first versions of the company's...
.
See also
- Extreme programmingExtreme ProgrammingExtreme programming is a software development methodology which is intended to improve software quality and responsiveness to changing customer requirements...
- Spiral modelSpiral modelThe spiral model is a software development process combining elements of both design and prototyping-in-stages, in an effort to combine advantages of top-down and bottom-up concepts. Also known as the spiral lifecycle model , it is a systems development method used in information technology...
- Top-down and bottom-up designTop-down and bottom-up designTop–down and bottom–up are strategies of information processing and knowledge ordering, mostly involving software, but also other humanistic and scientific theories . In practice, they can be seen as a style of thinking and teaching...
- Paper prototyping