DECISIONAL GUIDANCE - Human-Computer Interaction and Management Information Systems: Foundations - page 73

• A user is configuring a computer that she plans to purchase online. She is asked how much
RAM she wants. The Web site provides information to help her choose.
• A user is shopping for a DVD player at an e-commerce Web site. The site asks her a series
of questions about her preferences and then recommends three models.
• A word processor supports seventy-five different fonts, listed alphabetically. After going
through about twenty of them, the user tires of the process and picks Century Gothic. Had he
gone through the whole list, he would have selected Verdana. The order of the items played
a role in which font was chosen.
These examples differ in many ways, but each represents a situation where the system affords
the user an opportunity to exercise discretion and also contains a feature—decisional guidance—
that could affect the choice the user makes.
The study of decisional guidance was motivated more than a decade ago by the observation
that all but the most restrictive of interactive systems afford their users a range of behaviors.
Understanding how the users of an interactive computer-based system behave—arguably the cen-
tral issue in designing and studying those systems—therefore depends on understanding (1) the
choices the system affords its users and (2) how the system's design features affect the choices
users make. The former issue—how a system allows or constrains user discretion—is referred to
as “system restrictiveness.” The latter—how a system affects user behavior subject to those
constraints—is referred to as the system's “decisional guidance” (Silver, 1990, 1991a, 1991b).
The modifier “decisional” is significant because it distinguishes decisional guidance from the
“mechanical guidance” much more commonly found in interactive systems. While mechanical
guidance helps users with the mechanics of how to invoke and use a system's functionality—for
example, by providing help screens or tool tips—decisional guidance addresses the more sub-
stantive issue of how users exercise their discretion: which functions they select and how they
behave while using them. For instance, mechanical guidance might provide a list of available func-
tions, whereas decisional guidance might provide information about each function. Mechanical
guidance might identify what to click to invoke a particular function, whereas decisional guidance
might help determine which function to invoke. Mechanical guidance might indicate that a given
input must be non-negative, but decisional guidance might help the user determine the most
appropriate input value.
Decisional guidance was first studied in the context of decision support systems (DSS)—systems
that affect, or are intended to affect, how people make decisions (Silver, 1991b). DSS constituted
the first venue for exploring this attribute, in part, because DSS were among the first interactive
computer-based systems studied by the information systems field. More significantly, decisional
guidance was introduced in the DSS context because the concept is essential for truly under-
standing DSS. Computer-based decision support focuses on the processes through which users
make decisions and the outcomes of those processes. The many choices that users make when
selecting among and interacting with the system's functionality—the decision aids—determine
the process and outcomes. Understanding how a system's features affect those choices—that is,
which decision aids users employ and what inputs they supply—is therefore central to studying
or designing DSS. And that is precisely what decisional guidance is about.
In the context of DSS, decisional guidance was defined as follows:
Decisional Guidance: How a Decision Support System enlightens or sways its users as
they structure and execute their decision-making processes—that is, as they choose among
and use the system's functional capabilities. (Silver, 1991a, p. 107).