Information Technology Reference
In-Depth Information
Fig. 1.
CREAM model
In CREAM, Hollnagel [6] characterized the erroneous actions as a set of generic
relation-ships between the human actions and what can be observed in terms
of task goal achievement. Hollnagel calls
phenotype
the patterns of erroneous
action that are observable and
genotype
the patterns in the underlying causal
mechanisms that lead to phenotypes. These statements are based on genetic
metaphors. The phenotypes are structured in simple (concerning one single ac-
tion) and complex (covering complex sets of actions) phenotypes. The erroneous
action are classified as follows (Fig. 1) :
1.
Repetition
: The previous action (or set of actions) is repeated.
2.
Inversion
: The order of two neighboring actions is reversed.
3.
Omission
: An action is not carried out. This can be inside a sequence of
actions or - very often - the omission of the last action(s) of a series.
4.
Delay
: An action (or set of actions) started too late.
5.
Premature action
: An action (or set of actions) started too early, e.g., before
a signal was given or the required conditions had been established.
6.
Replacement
: A simple task (action) is replaced by another simple task
(action). Both are subtasks of a more general task.
7.
Insertion
: A simple task (action) belongs to the same general task is added
in a sequence.
8.
Inclusion
: A simple task (action) is an inclusion when it is added in a
sequence and has no link with the current task (not in the same hierarchy).
In the COCOM model, Hollnagel [5] defined four types of control mode corre-
sponding to time zones within which an agent can operate :
1.
Strategic
: the agent has a broad time horizon and looks ahead at higher-level
goals, having both an overall and a detailed view of the work system.
2.
Tactical
: this mode characterizes situations where performance more or less
follows a known procedure or rule. The user's time horizon goes somewhat
beyond the dominant needs of the present, but planning has a limited range.
