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representation and then defining and ordering the set of information-processing and problem-solving
activities to be performed” (Silver, 1991a, p. 111). The second level, referred to as executing the
process, “entails actually performing the various information-processing and problem-solving activ-
ities” (Silver, 1991a, p. 111). More generic identifiers than “structuring” and “executing” will be
useful in moving beyond DSS. The target of guidance for structuring the process can be viewed as
support for choosing among the system's functional capabilities. Guidance for executing the process
is guidance while using a given functional capability, which includes controlling the function,
selecting among the options it offers, and supplying the inputs it requires.
Forms: Suggestive Versus Informative Guidance
In everyday speech, “guidance” most often refers to steering someone or something in a given
direction. Decisional guidance, however, may be directive or may be non-directive, informing
users without steering them toward a given choice. By analogy, consider guidance for a motorist.
Directive guidance would be of the form, “Bear right at the fork!” But a signpost showing “North”
to the left and “South” to the right would also be a guide.
Decisional guidance that is directive is referred to as suggestive guidance , defined as guidance
that “makes judgmental recommendations (what to do, what input values to use) to the decision
maker” (Silver, 1991a, p. 112). The term “suggestive” emphasizes that it is non-restrictive; the
user may follow the suggestion or not. Non-directive guidance is referred to as informative guid-
ance, defined as providing “pertinent information that enlightens the decision maker's judgment
without suggesting how to act” (Silver, 1991a, p. 112). With informative guidance, the user draws
his or her own conclusions about the most desirable action to take. Table 6.2 provides examples
of each form of guidance for each target (structuring and executing the process).
Some researchers have characterized decisional guidance only as a means of directing users.
From the perspective of understanding how system features affect behavior, both suggestive and
informative guidance require study. And from the perspective of practice, each represents a fea-
ture that might be appropriate for a given design. So identifying and distinguishing the two forms
of guidance seems best.
Modes: Predefined, Dynamic, and Participative
From where does the substance of guidance come? “Guidance mechanisms operate in one of three
modes: predefined, dynamic, or participative. In the first case, the designer predefines the specific
suggestions or the particular information displays and builds them into the guidance mechanism.
In the other two cases, the designer constructs the guidance mechanism only; the mechanism then
generates the suggestions and informational displays either itself by learning dynamically over
time or with the active participation of the decision maker” (Silver, 1991a, p. 115).
Scope: Short- and Long-Range
Decisional guidance is usually delivered when the user confronts a choice—that is, when he
or she is about to exercise discretion. This guidance, focused on the immediate issue, is referred
to as short-range guidance. But sometimes, especially when the user is structuring a decision-
making process, the user may want to plan ahead and formulate the whole process, or at least, sev-
eral steps of the process. Guidance that supports a series of judgments is called long-range
guidance.
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