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Efficient Mechanisms under Unawareness

Kym Pram, Burkhard C. Schipper

TL;DR

The paper tackles efficient mechanism design under unawareness by introducing dynamic direct elaboration mechanisms that pool and raise awareness among agents, implementing utilitarian ex-post efficient outcomes at the pooled awareness level with transfers inspired by VCG. Static VCG fails in this setting, motivating a dynamic, belief-free approach that elicits both payoff types and awareness elaborations through a mediator, ensuring efficient outcomes via conditional dominant strategies. It further develops budget-balance variants (Clarke-style) that can achieve no deficit, analyzes participation constraints, and presents a procurement mechanism for ex-ante unforeseen contingencies that preserves efficiency, budget balance, and seller participation. Overall, the work links unawareness to interdependent valuations and demonstrates how awareness-elaboration mechanisms can attain efficient allocations in multi-agent settings with private values and quasi-linear utilities, offering practical insights for complex procurement and contracting.

Abstract

We study the design of efficient mechanisms under asymmetric awareness and information. Unawareness refers to the lack of conception rather than the lack of information. Assuming quasi-linear utilities and private values, we show that we can implement in conditional dominant strategies a social choice function that is utilitarian ex-post efficient when pooling all awareness of all agents without the need of the social planner being fully aware ex-ante. To this end, we develop novel dynamic versions of Vickrey-Clarke-Groves mechanisms in which types are revealed and subsequently elaborated at endogenous higher awareness levels. We explore how asymmetric awareness affects budget balance and participation constraints. We show that ex-ante unforeseen contingencies are no excuse for deficits. Finally, we propose a modified reverse second price auction for efficient procurement of complex incompletely specified projects.

Efficient Mechanisms under Unawareness

TL;DR

The paper tackles efficient mechanism design under unawareness by introducing dynamic direct elaboration mechanisms that pool and raise awareness among agents, implementing utilitarian ex-post efficient outcomes at the pooled awareness level with transfers inspired by VCG. Static VCG fails in this setting, motivating a dynamic, belief-free approach that elicits both payoff types and awareness elaborations through a mediator, ensuring efficient outcomes via conditional dominant strategies. It further develops budget-balance variants (Clarke-style) that can achieve no deficit, analyzes participation constraints, and presents a procurement mechanism for ex-ante unforeseen contingencies that preserves efficiency, budget balance, and seller participation. Overall, the work links unawareness to interdependent valuations and demonstrates how awareness-elaboration mechanisms can attain efficient allocations in multi-agent settings with private values and quasi-linear utilities, offering practical insights for complex procurement and contracting.

Abstract

We study the design of efficient mechanisms under asymmetric awareness and information. Unawareness refers to the lack of conception rather than the lack of information. Assuming quasi-linear utilities and private values, we show that we can implement in conditional dominant strategies a social choice function that is utilitarian ex-post efficient when pooling all awareness of all agents without the need of the social planner being fully aware ex-ante. To this end, we develop novel dynamic versions of Vickrey-Clarke-Groves mechanisms in which types are revealed and subsequently elaborated at endogenous higher awareness levels. We explore how asymmetric awareness affects budget balance and participation constraints. We show that ex-ante unforeseen contingencies are no excuse for deficits. Finally, we propose a modified reverse second price auction for efficient procurement of complex incompletely specified projects.

Paper Structure

This paper contains 12 sections, 6 theorems, 41 equations, 3 figures.

Table of Contents

  1. Introduction
  2. Related Literature
  3. Model
  4. Payoff Types with Unawareness
  5. Failure of Static VCG Mechanisms
  6. Dynamic Direct Elaboration Mechanisms
  7. Efficient Implementation
  8. Budget Balance
  9. No Deficit
  10. Participation Constraints
  11. Procurement under ex-ante Unforeseen Contingencies
  12. Discussion

Key Result

Theorem 1

The dynamic elaboration VCG mechanism truthfully implements in conditionally dominant strategies a utilitarian ex-post efficient outcome under pooled awareness.

Figures (3)

  • Figure 1:
  • Figure 2: Payoff Types in Example 2
  • Figure 3: Payoff Types in Example 3

Theorems & Definitions (17)

  • Definition 1
  • Definition 2: Dynamic Direct Elaboration Mechanism
  • Definition 3
  • Definition 4
  • Definition 5: Dynamic Elaboration VCG Mechanism
  • Theorem 1
  • Proposition 1
  • Definition 6: Budget Balance
  • Proposition 2
  • Definition 7: No deficit
  • ...and 7 more