Committee choice and the core under supramajority rule: Results from simulation of majority choice in 2-dimensional space

While simple-majority choice by committees is generally unstable, supramajority rule has been demonstrated to yield nonempty sets of stable outcomes: outcomes in the core. This paper reports results of a computer simulation of majority choice by committees under supramajority rule. The object is to explore the transition from unstable to stable committee choice with increasing supramajority rules. The findings are that supramajority rule limits the instability of committee choice; that stable committee choice is no more predictable than unstable committee choice; and that an optimal supramajority rule can be specified which minimizes instability and maximizes the predictability of committee choice. In all of the results, simple-majority rule plays virtually no role.