Selecting a Keyboard

By Sean Chen, Alan Hedge, and Dwight Owsen

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JULY 2005 - The key to good ergonomics, the science of adapting physical devices to the human body, is to match the design of the technology to the needs and characteristics of the user. Identifying what type of keyboard is best suited for an individual based on her specific needs should be left for physical therapists to evaluate.

The keyboards discussed below use different physical designs to improve typing safety and performance. Some keyboards were specifically designed for people injured by traditional keyboard formats or for those with a physical disability that affects their typing ability, such as a one-handed typist. Other keyboards are designed for the general user.

Ergonomic keyboards are more expensive than conventional ones, but this may change as they become more widespread. Most designs offer some health benefits by reducing injury risk factors. Moreover, many designs result in demonstrable productivity improvements, with users improving their overall work speed by up to 80%. These benefits might soon outweigh the initial costs of ergonomic designs.

An effective ergonomic design must meet the following criteria:

  • It must fit the job to be done and enhance work performance, in terms of either the quantity or the quality of work.
  • It must fit the user in terms of its size and physical shape.
  • It must protect the user against injury.
  • It must be comfortable and easy to use.

The Development of Ergonomic Keyboards

In the late 1930s, researcher August Dvorak improved the standard layout of the alphanumeric keys by developing an alternative layout to the familiar QWERTY (derived from the first six letters on the third row of keys) keyboard layout that most people use today. Unlike QWERTY, the DVORAK layout allows typists to type more than twice as many words from the home row keys, which, theoretically, should greatly improve typing speed.

Since the 1970s, all computers sold in the U.S. support both QWERTY and DVORAK keyboard layouts. Despite more than a half-century of research and debate about the advantages of the DVORAK layout, the QWERTY layout has remained the de facto keyboard and, despite its limitations, most users seem to accept this now familiar layout. A recent study by the National Institute of Occupational Safety and Health compared the two layouts and failed to find any performance or postural benefits with DVORAK.

Since the mid 1960s, there have been numerous other redesigns of the computer keyboard. Today several varieties of “ergonomic” keyboards are available. All offer some benefits to some users, but each has limitations. Apart from the conventional keyboard, none of these designs has gained widespread acceptance.

Conventional keyboards have evolved substantially over the past 20 years as well. Keyboards have become flatter; function keys are now on a top row; key mechanisms have become “lighter,” requiring less force; and most keyboards have a cursor keypad and a numeric keypad. Thus, most ergonomic experts conclude that, for the average user of average size and average typing skill, the improved conventional computer keyboard is good enough. The design is a familiar to most users, and is cost-effective.

Ergonomic Designs to Suit Individual Problems

Problems with using a conventional keyboard can be related to the posture or the hands, the keying forces, and the repetitive motion. Consequently, keyboard makers have developed a variety of alternative ergonomic keyboard designs to solve many of the problems and to improve work performance for suitable users. Ergonomic keyboard designs fall into the following categories:

Fixed-angle split keyboards. These keyboard designs split the alphanumeric keys at a fixed angle and slightly tent the keyboard up (see Microsoft Natural, Some research evidence indicates reduced discomfort because of reduced ulnar deviation (i.e., the lateral bending of the hands). These designs work better for broader, larger-framed individuals and pregnant women because they put the arms in a better position to reach around the front of the body. The designs usually address the issue of wrist extension (i.e., upwards bending of the hands), however, which is a more important musculoskeletal injury risk factor than ulnar deviation. Hunt-and-peck typists will find split keyboards more difficult to use. The keyboards are generally larger and wider than conventional keyboards, which in some situations can put the mouse too far out to the side of the keyboard.

Multitouch fixed-angle split keyboards. These do not use conventional keys but have a touch-sensitive surface that allows the user to key and mouse in the same physical space (Touchstream; This design also allows users to control many computer commands using simple finger gestures, again all performed on the same physical area. There is a learning curve, but as users become proficient, the overall speed of computer work performance can increase by more than 80%.

Adjustable-angle split keyboards (Goldtouch; allow users to change the split angle to suit their own needs. Often their makers link the split angle to the degree of tenting of the keyboard as well. Some research evidence indicates reduced discomfort with this kind of design because of reduced ulnar deviation. These designs do not usually address wrist extension issues. The user has to decide on the split angle, which means that they may need some training, and some users might end up with a split angle that is inappropriate for them. There is also a multitouch adjustable-angle split keyboard (Touchstream LP; Split keyboards are always difficult for hunt-and-peck typists to use, and these designs are often expensive. Touch typists should be able to move back and forth easily between straight keyboards and split keyboards.

The makers of completely split keyboards (Kinesis; split the left-hand and right-hand portions of the keyboard completely apart. In some designs, keyboard makers present the keys in a scooped design that allows the hands to rest in a more neutral posture for typing. Some research evidence indicates reduced discomfort because of reduced ulnar deviation and reduced wrist extension. Unfortunately, there is more of a learning curve, and research shows that initial performance can suffer a 50% slowing of typing speed. Again, touch typists have an advantage here. Completely split keyboards are especially difficult for hunt-and-peck typists to use, and some of them are very expensive.

Vertically split keyboards resemble an accordion. The user types with the hands facing each other (Safetype;; consequently, the typist cannot easily see the keys. This design works well to reduce ulnar deviation and wrist extension, but it is important not to have the keyboard too high because the chest and shoulders can suffer fatigue. This design is almost impossible for hunt-and-peck typists to use, and because it is a specialist keyboard, it is expensive.

Chordic keyboards (Twiddler; have a smaller number of keys and letters; combinations of keys in chords generate characters. One-handed and two-handed designs are available. Research shows that this is like learning stenography; learning the chords that correspond to characters requires about 80 hours to get to moderately fast—a high learning curve. These keyboards are more expensive than regular keyboards but can be useful to some users, especially those with special needs, such as a blind user or one with severely arthritic hands.

Specialist keyboards (Datahand,; and Orbitouch, comprise several different designs to assist users with some physical limitation or who wish to type in a different way. The Datahand allows users to rest their hands on a series of switches that detect different directions of finger movements, and these generate the characters. The Orbitouch lets users rest their hands on two domed surfaces and then move these surfaces to generate the characters. Specialist keyboards often result in slower typing and can have significant learning curves, so they are not for most users. Like other alternative keyboard designs, they are expensive, and touch typists more easily adopt this form than nontouch typists do.

One-handed keyboards (Half-QWERTY; come in several alternative designs. The Half-QWERTY keyboard uses the same kinds of keys found on a regular keyboard, but each key functions in two modes to generate all of the characters of a regular keyboard in a smaller area. One-handed chordic keyboards (e.g., BAT, and one-handed multitouch keyboards are also available.

Which Keyboard Design Is Best?

No single design is best for everyone. The conventional keyboard remains the most common design because it can be mass-produced at low cost and is familiar to most users. However, businesses may find that other designs increase productivity and offer less risk of injury. Consequently, keyboard makers have developed various ergonomic designs to address different user needs and different work situations.

Sean Chen, PhD, is a professor at Loyola Marymount University, Los Angeles, Calif.
Alan Hedge, PhD,
is a professor at Cornell University, Ithaca, N.Y.
Dwight Owsen, ABD, is an instructor of accounting at Long Island University, Brooklyn, N.Y.




















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