Saturday, November 10, 2018

Obvious manipulations by Pete Troyan and Thayer Morrill

Here's a paper motivated by the fact that (obviously:) there are going to be many more mechanisms that aren't obviously manipulable than there are mechanisms that are obviously strategy proof, or even strategy proof...

Obvious Manipulations
Peter Troyan, Thayer Morrill∗ (*in random order)
October 3, 2018

Abstract: A mechanism is strategy-proof if agents can never profitably manipulate, in any state of the world; however, not all non-strategy-proof
mechanisms are equally easy to manipulate - some are more “obviously”
manipulable than others. We propose a formal definition of an obvious
manipulation and argue that it may be advantageous for designers to
tolerate some manipulations, so long as they are non-obvious. By doing
so, improvements can be achieved on other key dimensions, such as
efficiency and fairness, without significantly compromising incentives.
We classify common non-strategy-proof mechanisms as either obviously
manipulable (OM) or not obviously manipulable (NOM), and show that
this distinction is both tractable and in-line with empirical realities
regarding the success of manipulable mechanisms in practical market
design settings

"Intuitively, a manipulation classified as “obvious” if it either makes
the agent strictly better off in the worst case ...or it makes the agent strictly better off in the best case..."

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