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Structured group processes 321
said to the engineers that they would report the engineers’ concerns to
the Level II NASA management, but they did not.
Structured group processes
Awareness of the factors that can degrade group decision making
combined with the implicit belief that group judgment can potentially
enhance decision making has led to a number of structured methods to
enhance group decision making by removing or restricting interpersonal
interaction and controlling information flow. One such major method
has been Delphi. 14 Essentially, Delphi consists of an iterative process for
making quantitative judgments. The phases of Delphi are:
(1) Panelists provide opinions about the likelihood of future events, or
when those events will occur, or what the impact of such event(s)
will be. These opinions are often given as responses to questionnaires
which are completed individually by members of the panel.
(2) The results of this polling of panelists are then tallied and statistical
feedback of the whole panel’s opinions (e.g. range or medians) are
provided to individual panelists before a repolling takes place. At
this stage, anonymous discussion (often in written form) may occur
so that dissenting opinion is aired.
(3) The output of the Delphi technique is a quantified group ‘consensus’,
which is usually expressed as the median response of the group
of panelists.
Without any repolling, simply utilizing the median of a group’s opinions
on, say, the unit sales of a new product in the first year of production will
provide more accuracy than that due to at least 50% of the individual
panelists. To see this, consider Figure 12.2.
In Figure 12.2(a), where the true answer lies outside the range of
estimates, the group median is more accurate than one half of the group
(the gray shaded area). In Figure 12.2(b), where the true answer lies
inside the range of estimates, the group median is more accurate than
the majority of panelists (the gray shaded areas).
With repolling and feedback, it is assumed that the median response of
the group shifts nearer to the true value of the outcome to be predicted.
Improvement is thought to result from opinion changes in ‘swingers’,
who change their less firmly grounded opinions, and the opinion stability
of ‘holdouts’, who are assumed to be more accurate than ‘swingers’.