# Hybrid Mechanisms: Trading off Strategyproofness and Efficiency of Random Assignment Mechanisms

arXiv: https://arxiv.org/abs/1303.2558 · HTML: https://mlsanity.com/paper/1303.2558/

## Key facts

- Cited by 1 papers in the map (data through 14 Oct 2026).
- First posted on arXiv 11 Mar 2013.

## Built on by (most cited first, 1 of 1)

- [Deep Learning for Two-Sided Matching](https://mlsanity.com/paper/2107.03427/) (2021)

## Abstract (arXiv)

Severe impossibility results restrict the design of strategyproof random assignment mechanisms, and trade-offs are necessary when aiming for more demanding efficiency requirements, such as ordinal or rank efficiency. We introduce hybrid mechanisms, which are convex combinations of two component mechanisms. We give a set of conditions under which such hybrids facilitate a non-degenerate trade-off between strategyproofness (in terms of partial strategyproofness) and efficiency (in terms of dominance). This set of conditions is tight in the sense that trade-offs may become degenerate if any of the conditions are dropped. Moreover, we give an algorithm for the mechanism designer's problem of determining a maximal mixing factor. Finally, we prove that our construction can be applied to mix Random Serial Dictatorship with Probabilistic Serial, as well as with the adaptive Boston mechanism, and we illustrate the efficiency gains numerically.