GMAA: A DSS Based on the Decision Analysis Methodology - Application Survey and Further Developments - Efficient Decision Support Systems: Practice and Challenges from Current to Future - page 271

organizational areas responsible for cleaning services, finance and other departments or
representatives, such as legal affairs and customer service.
An objective hierarchy with the following five main top-level objectives was built: Delivery
conditions and human resources , which accounts for how consistent and coherent the human
resources allocated to the services are; Technical merit and resources , which it is an important
efficiency factor leading to a significant reduction in labor cost; Price , which represents the
lowest price offered by suppliers; Quality control procedures , which accounts for accredited
quality certifications and how quality systems and procedures are deployed; and Graffiti
prevention and cleanup , which is one of the most common incidents detracting from the
appearance of the underground buildings. Twenty-one lowest-level objectives were
included in the above objective hierarchy, see Fig. 6, and the corresponding attributes were
established to indicate to what extent they were achieved by the respective offers.
Following the European Community directives, stating that criteria should be set and at
least ordered by importance before examining the offers, DM preferences were quantified
before identifying offers. Fig. 7 illustrates attribute weights. The most important attribute in
the decision was Price , with an average normalized weight of 0.513, followed at a distance
by workload, quantity of technical means, number of quality certifications, experience with
graffiti and workload allocation, with average normalized weights of 0.125, 0.082, 0.052,
0.052 and 0.036, respectively.
Next, the feasible supplier offers were identified and measured in terms of the 21 attributes.
The performances for the six offers considered and the component utilities assessed are
reported in (Jiménez et al., 2007). Note that uncertainty about some of the performances was
accounted for by means of percentage deviations, which represent tolerances or correction
factors for offers where information provided by the bidders was somewhat ambiguous or
was not clear enough.
Fig. 6. Objective hierarchy in the selection of a supplier for cleaning services