• technicians to keep the computers and networks working - $1,170
• linking to a network and required basic software - $1,730
• training and technical support - $3,510
• employees wasting time (surfing, customizing, futzing) - $5,590

This makes the total annual cost, not $1,000, but closer to $13,000. In addition, because many systems are so difficult to use (i.e., they have poor user interfaces), employees can take up to 10% of their time helping co-workers with computer problems. This increases the annual cost of a PC up to $23,500.

Studies show that the factor most closely linked to these support costs is the extent to which the user interface matches the way users think and work. Even though designing high quality user interfaces is difficult, effectively applying usability research could make computer systems dramatically more productive, easier to use and cheaper to support.

For example, usability specialists helped improve the overall productivity of the New York Stock Exchange. They participated in upgrading the four primary computer systems used on the trading
floor. The designers developed prototypes, conducted usability tests and made many revisions. Overall productivity increased dramatically. The workload capacity doubled (they can now handle over 2 billion shares a day), and the error rates fell by a factor of 10.

 

Efficient Design

Can good usability design guarantee efficient usage of computer systems?

Bhavnani and John (1997) observed that many veteran employees do not use computer tools efficiently even after formal training and many years of experience. Adequate design seems to lead to sufficient usage, but it does not guarantee efficient usage. It appears that efficient usage requires knowledge that is beyond the design of the system itself.

One way to help ensure efficiency is to effectively use “aggregation.” Aggregation is the ability to group disjoint elements, and then manipulate the group with an appropriate operator. For example, selecting 10 items in a folder and then deleting them all by pressing the delete key. Or selecting several elements in a graphic and applying a color or filter to all elements simultaneously. Even though aggregation can be a powerful mechanism for helping to ensure efficiency, studies suggest that even experienced users have trouble effectively applying aggregation.

The issue of efficiency seems to arise when there is more than one way of performing tasks, particularly complex tasks. To take full advantage of aggregation designers should:

• Provide few, but efficient, ways to perform,
• Design user interfaces (and required training) to include strategies for the effective use of aggregation,
• Users should be encouraged to find and use more effective aggregation strategies,
• and Systems should detect when aggregation is not being used, and suggest appropriate aggregation strategies.

 

References

Bhavnani, S.K. and John, B.E., From Sufficient to Efficient Usage: An Analysis of Strategic Knowledge, Proceedings of CHI'97, 91-98 (1997).

Gibb, W.W., Taking computers to task, Scientific American, July, 82-89 (1997) .