Encyclopedia of Environmental Science and Engineering, Volume I and II

328 ENVIRONMENTAL ASSESSMENTS AND RELATED IMPACTS

each of the factors involved. Typical environ-

mental impact studies may include of the order

of 25 to 35 different environmental factors for

consideration.

3. Once the environmental factors are determined by
   the nominal group, the consulting group gener-
   ally develops criteria for the nominal group to aid
   them in weighting the impact of each environmen-
   tal factor involved for the sites in question so that
   the nominal group can “score” each of the sites
   involved.

For example, assume that the nominal group considered

noise as a factor in the siting of an airport, and further, they

judged that noise impacts should have an importance weight-

ing of 87 (out of 100).

In order to assess the impacts of sound generation from

a proposed airport on the potential sites to be considered,

the consulting group would review the demographics and

housing characteristics of the sites under consideration and

develop scoring criteria which is applied to all sites such as

in the following example:

SCORING LEVEL: SOUND LEVEL

CONDITIONS

0 points — no dwelling unit within

2 miles of the proposed air-

port boundaries.

1 point — less than 5 dwelling units

within 2 miles of the pro-

posed airport boundaries.

2 points — between 6 and 25 dwelling

units within 2 miles of the

proposed airport boundaries.

3 points — between 26 and 75 dwelling

units within 2 miles of the

proposed airport boundaries.

4 points — greater than 75 dwelling

units within 2 miles of the

proposed airport boundaries.

As such, if the area surrounding a particular site in ques-

tion had between 6 and 25 dwelling units within 2 miles of

the airport boundaries, it would achieve a score of 87 
 2, or

174 points for the factor of noise, whereas, if it had no dwell-

ing units within 2 miles, it would obtain a score of 87 
 0,

or zero points for the factor of noise. For this system scoring

approach, the higher the point value accrued for the sites

would indicate the sites most environmentally sensitive to

impacts resulting from a proposed airport.

Each environmental factor would be scored by the nomi-

nal group in a fashion as noted above, and the cumulative

score for each site would be tallied and the sites ranked

accordingly in terms of the least to the greatest sensitivity to

the proposal.

In order to insure the integrity of the nominal group

(i.e., to avoid potential conflicts of interest in their voting

behavior), the sites they would be scoring would be “masked”

so that they would not be able to identify the sites in question

from the data provided to them by the consulting groups.

Normally, professionals from the consulting group are

available to the nominal group to respond to any technical

questions the group might have in formulating their numeri-

cal evaluations in the process. Also, in general, a series of

rounds of voting would be utilized until the nominal group

felt that they had reached a consensus.

Use of the Nominal Group Technique methodology

for site selection purposes has the following recognized

benefits:

• It provides a resultant site or sites for ultimate
  selection purposes which is determined on a
  quantitative basis.


• The nominal group members are unbiased in that
  they do not know the sites they are evaluating
  during the site selection process.


• The process is democratic, and interactive ses-
  sions between members allows for interchange
  and stability of the process.


• The group members are the decision makers
  rather than the consultants and, as such, they (i.e.,
  the public) govern their own destiny in the site
  selection process.

The Nominal Group process is an excellent tool for

consultants and/or County or State Agencies, in applica-

tions which face strong opposition, to provide the burden

of decision-making on the Nominal Group Committee.

The effectiveness of the Nominal Group Technique Method

in the site selection process is related to the following factors:

• The size of the nominal group.


• The credentials of the nominal group to conduct
  assessments.


• The method of selection of the nominal group
  members.


• The charge given to the group before and during
  the site selection processes.


• The role of the group and their involvement (if
  any) in selecting exclusionary criteria.


• The basis utilized for weighting the environmental
  issues considered by the group members.


• The basis utilized for scoring each of the issues
  considered by the group members.


• The analysis and interpretation of the data
  received from the process and its related statisti-
  cal significance.

Depending upon how the above issues are handled in

a particular study, the results can range from excellent to

ridiculous, and the Nominal Group Members can play roles

ranging from enlightened decision-makers to manipulated

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