Methodology I: Task Analysis - Foundations for Designing User-Centered Systems - page 312

were followed for the incidents selected by each of the eight participants, and a
critical cue inventory—highlighting the cues that clinical staff paid attention to—
and situation assessment records—which describe how the incident unfolded in
terms of cues, goals, expectations, and decisions—were developed for each inci-
dent. These highlighted aspects such as the importance of having a distinctive
alarm for FLORENCE because the unit already has several alarms sounding on a
fairly regular basis, and the hierarchy of decision making which flattens when
dealing with acute incidents.
Finally, observation was used to capture details of how clinical staff work
in situ to treat babies with RDS. RDS is self-regulating, and usually lasts around
72 h. The treatment of two babies was recorded using timed note taking—the unit
is a high stress situation, so video recording was not a viable option—over a 2-h
period. The first baby was moved off the unit after 1 day; the second baby was
observed on three consecutive days all at the same time of day. The results showed
how often staff interacted with the equipment around the babies' cots under normal
conditions and when an alarm sounded.
The results of the CTA were analyzed and used to inform the development of
FLORENCE. These included decisions about the interface (e.g., the need for
instructions about changes to ventilator settings to be precise and unambiguous,
such as ''increase PIP by 2-16''), as well as training (e.g., staff need to learn how
to prioritize their response to FLORENCE's alarm) and more general physical
ergonomics concerns (e.g., space is needed around the baby's cot to accommodate
the PC running FLORENCE).
11.4.3 Summary
As its name suggests, CTA is particularly suited to analyzing the cognitive pro-
cesses and products that people use when performing tasks. It is not so good at
dealing with the work context in which performance takes place (although using
rich pictures analysis does provide at least a partial solution, e.g., see Baxter et al.
2005 ). Carrying out a CTA can be quite time consuming, particularly when the
selected methods require access to experts. CTA also requires that the analyst(s)
are competent in carrying out a range of methods. Furthermore, it requires a high
level of skill to be able to interpret the results of several methods in a holistic way
so that they can be presented to the system developers.
11.5 GOMS
GOMS is an acronym for Goals, Operations, Methods, and Selection rules (Card
et al. 1980 , 1983 ). It is a method that can be used as part of a CTA, but we include
it in its own right because of its close relationship with the field of HCI.