Abstract:
The present study presents a comparative analysis of different group aggregation
methods adopted in AHP by testing them against social choice axioms with a case study of
Delhi transport system. The group aggregation (GA) methods and their correctness were tested
while prioritizing the alternative options to achieve energy efficient and less polluting transport
system in Delhi
It was observed that among all group aggregation methods, geometric mean method
(GMM) - the most widely adopted GA method of AHP - showed poor performance and failed to
satisfy the most popular “pareto optimality and non-dictatorship axiom” raising questions on
its validity as GA method adopted in AHP. All other group aggregation methods viz. weighted
arithmetic mean method with varying weights and equal weights (WAMM, WeAMM) and
arithmetic mean of individual priorities (AMM) resulted in concurring results with the
individual member priorities.
This study demonstrates that WeAMM resulted in better aggregation of individual
priorities compared to WAMM. Comparative analysis between individual and group priorities
demonstrates that the arithmetic mean (AMM) of priorities by individual members of the group
showed minimum deviation from the group consensus making it the most suitable and simple
method to aggregate individual preferences to arrive at a group consensus.
