Problem structure: The selection of the correct methodology related
to the structure decision making problems is really important
for the decision maker. AHP is preferred in the situations when the
decision making problem can be dissociated as criteria, subcriteria
and alternatives, and the effect of each subject is demanded for
measuring. Furthermore, since it is necessary to make pairwise
comparisons in all the levels of hierarchy, it gets harder to perform
AHP as the number of alternatives and criteria increase. On the
other hand, AHP can be performed easily disregarding the data
applying evaluation of alternatives based on criteria is quantitative
or qualitative. TOPSIS method draws attention as its simplicity in
perception and use. TOPSIS and ELECTRE methods can be performed
easily when the number of alternatives and criteria is too
many. In addition, these methods are more suitable in cases when
the data is provided as objective and quantitative.
Final results: In AHP and TOPSIS methodologies, after completing
the method steps, global and net ranking is attained among
alternatives. In ELECTRE I method, the result input acquired is in
the shape of kernel. The preference and ranking relationships
among alternatives are determined with this kernel. In ELECTRE
II method, thus, a two way ranking is acquired and the outranking
relations among alternatives are determined through associating
the two way ranking. In ELECTRE III method, as a result of the comparison
of concordance and discordance indexes with concordance
and discordance thresholds partial ranking is acquired at the parallel
of reliability matrix formed among alternatives (Karagiannidis &
Moussiopoulos, 1997).
Basic results attained from the comparative analysis of decision
making methodologies are given in Table 1. On the other hand,
Grey Theory is used in the solution of decision making problems
related to grey systems defined as a little information and poor
data known on specific scale and unknown on specific scale (Yuan,
2007).