Introducing User-Centered Systems Design - Foundations for Designing User-Centered Systems - page 11

1.3.2 Benefit 2: Financial Savings
Designing to support users can save companies money, even of the order of
millions of dollars. One case is Nynex, the New York telephone company, in the
early 1990s. The toll and assistance operators (TAO) are the people who help you
when you dial ''0''. They help customers with collect calls, billing, and other more
complex calls. In the early 1990s Nynex was considering upgrading their TAO
workstation. They had a room with about 100 of these operators; it was believed
that new graphical user workstations could improve productivity. The cost of
upgrading all the workstations was going to be about $500,000 (in 1990s dollars).
The company engaged a team of applied psychologists to look at how much faster
the new workstations would be. The results of a task analysis (using a form of
GOMS which is described in more detail in Chap. 11 ) suggested that the new
workstations would not be faster, but would, in fact, be 4% slower to operate. This
may seem like a small difference, but a 4% reduction in productivity was going to
cost Nynex $2.4 million a year—in addition to the cost of the workstations.
Nynex ran a study to discover how much faster the new workstations would
really be. After allowing time for the operators to learn to use the workstations, the
operators' performance plateaued about where it was predicted—4% slower.
NYNEX now claims that this study saved them $2.4 million per year. The user
study paid for itself in the first week (see Gray et al. 1992 , 1993 for more details).
The slowdown in operator performance was not caused by the fact that the new
workstations simply required the user to take more steps to achieve the same goal.
The reason was the new interface did not allow multi-tasking; the operators could
not type while waiting for the caller to speak which they could with the old.
Improved computer processor speed could not compensate for the loss in parallel
activity the users had with the previous design.
The NYNEX example reveals the benefits of considering people—in this case
the operators—even when there does not appear to be a problem. In many
instances the main advantage of studying people using systems—that is, con-
ducting ''user studies''—is to identify where people make errors, so that we can
prevent them or mitigate their consequences in the final product. People often do
not type what they want to type, and sometimes push buttons that they did not
intend to push. Strangely enough, this problem can be more prevalent amongst
highly-skilled expert users, than amongst beginners. Errors that occur when
someone knows the right thing to do, but accidentally does something different, are
commonly referred to as 'slips' to distinguish them from mistakes, where the
action is taken on the basis of an incorrect plan (Norman 1981 ; Reason 1990 ).
These slips can also occur on well-practiced interfaces that do not attempt to
catch such slips. These slips can also be very expensive. A local paper (Centre
Daily Times, 15 Feb 2002, p. C38) reported that a financial services firm lost up to
$100 million because it executed a sell order of 610,000 shares at 16 yen instead of
the correct order of 16 shares at 610,000 yen (approximately 100 yen/US$).