Essays on robust mechanism design

Chapter 1: Under the average common value function, we select almost uniquely the mechanism that gives the seller the largest portion of the true value in the worst situation among all the direct mechanisms that are feasible, ex-post implementable and individually rational. Chapter 2: Strategy-proof, budget balanced, anonymous, envy-free linear mechanisms assign p identical objects to n agents. The efficiency loss is the largest ratio of surplus loss to efficient surplus, over all profiles of non-negative valuations. The smallest efficiency loss is uniquely achieved by the following simple allocation rule: assigns one object to each of the p−1 agents with the highest valuation, a large probability to the agent with the pth highest valuation, and the remaining probability to the agent with the (p+1)th highest valuation. When “envy freeness” is replaced by the weaker condition “voluntary participation”, the optimal mechanism differs only when p is much less than n. Chapter 3: One group is to be selected among a set of agents. Agents have preferences over the size of the group if they are selected; and preferences over size as well as the “stand-outside” option are single-peaked. We take a mechanism design approach and search for group selection mechanisms that are efficient, strategy-proof and individually rational. Two classes of such mechanisms are presented. The proposing mechanism allows agents to either maintain or shrink the group size following a fixed priority, and is characterized by group strategy-proofness. The voting mechanism enlarges the group size in each voting round, and achieves at least half of the maximum group size compatible with individual rationality.

A house, not a home? Examining the use of the private rented sector to resolve homelessness in Scotland

Changes to homelessness legislation in post-devolution Scotland have resulted in an expansion of rights for homeless households seeking formal assistance from local authorities. These changes have led to Scotland’s homelessness arrangements being considered among the most progressive in Europe. In recent years, however, the Scottish Government has increasingly promoted homelessness prevention and Housing Options approaches as a means by which homelessness might be avoided or resolved without recourse to statutory rights. As part of that, they have promoted greater use of the private rented sector (PRS) as a key housing option, with the potential to meet the needs of homeless households. The arguments made to support use of the PRS have much in common with arguments for privatisation in other areas of social policy, notably greater choice for the individual promoting better welfare outcomes, and competition among providers encouraging improvements in quality of service provision. Critics have argued that such benefits may not be realised and that, on the contrary, privatisation may lead to exclusion or act to worsen households’ outcomes. This thesis considers the extent to which the PRS has been utilised in Scotland to accommodate homeless households, and the consequences of this for their welfare. The thesis uses a combination of quantitative and qualitative methods. To examine trends in the use of the PRS, it presents quantitative analysis of the data on the operation of the statutory system and Housing Options arrangements, and of data from a survey of local authority homelessness strategy officers. To examine the consequences of this for homeless households, the thesis uses qualitative research involving face-to-face interviews with 35 homeless households across three local authority areas. This research considers the extent to which households’ experiences of homelessness, housing need and the PRS reflect the arguments presented in the literature, and how settled accommodation has impacted on households’ ability to participate fully in society. The research found an increasing but still limited role for the PRS in resolving statutory homelessness in Scotland, with indications that the PRS is being increasingly used as part of the Housing Options approach and as a means of resolving homelessness outside the statutory system. The PRS is being utilised to varying degrees across different local authority areas, and a variety of methods are being used to do so. While local authorities saw clear advantages to making greater use of the sector, a number of significant barriers including affordability, available stock and landlord preferences - made this difficult in practice. Research with previously homeless households in the PRS similarly found broadly positive experiences and views of the sector, particularly with regard to enabling households to access good quality accommodation in desirable areas of their choosing, with many households highlighting improvements relating to social inclusion and participation. Nevertheless, concerns around the security of tenure offered by the sector, repairs, service standards and unequal power relations between landlord and tenant persisted. As such, homeless households frequently expressed their decision to enter the sector in terms of a trade-off between choice and security.