Adaptive Contract Design for Crowdsourcing Markets: Bandit Algorithms for Repeated Principal-Agent Problems

Crowdsourcing markets have emerged as a popular platform for matching available workers with tasks to complete. The payment for a particular task is typically set by the task's requester, and may be adjusted based on the quality of the completed work, for example, through the use of "bonus" payments. In this paper, we study the requester's problem of dynamically adjusting quality-contingent payments for tasks. We consider a multi-round version of the well-known principal-agent model, whereby in each round a worker makes a strategic choice of the effort level which is not directly observable by the requester. In particular, our formulation significantly generalizes the budget-free online task pricing problems studied in prior work. We treat this problem as a multi-armed bandit problem, with each "arm" representing a potential contract. To cope with the large (and in fact, infinite) number of arms, we propose a new algorithm, AgnosticZooming, which discretizes the contract space into a finite number of regions, effectively treating each region as a single arm. This discretization is adaptively refined, so that more promising regions of the contract space are eventually discretized more finely. We analyze this algorithm, showing that it achieves regret sublinear in the time horizon and substantially improves over non-adaptive discretization (which is the only competing approach in the literature). Our results advance the state of art on several different topics: the theory of crowdsourcing markets, principal-agent problems, multi-armed bandits, and dynamic pricing.Comment: This is the full version of a paper in the ACM Conference on Economics and Computation (ACM-EC), 201

Dundee Discussion Papers in Economics 146:Welfare state, market imperfections and international trade

Within a two-sector-two-country model of trade with aggregate scale economies and unionisation, a more generous welfare state in one country increases welfare in that country and can have positive spillover effects on the other. Furthermore, synchronised expansions of social security are more welfare enhancing than unilateral ones. Our results counter the fears that a race to the bottom in social standards may result from the ‘shrinking-tax-base’ entailed by international capital mobility. While affecting trade patterns and income distribution, capital mobility interacts with welfare state policies in increasing welfare, even when capital flows out of the country that initiates the shock

Anomalies: Ultimatums, Dictators and Manners

Economics can be distinguished from other social sciences by the belief that most (all?) behavior can be explained by assuming that agents have stable, well-defined preferences and make rational choices consistent with those preferences in markets that (eventually) clear. An empirical result qualifies as an anomaly if it is difficult to "rationalize" or if implausible assumptions are necessary to explain it within the paradigm. This column will resume, after a long rest, the investigation of such anomalies

Disparities in Access to Health Insurance and Workers’ Compensation Benefit between Non-Contingent and Contingent Farm Workers in U.S. Agriculture

The share of contingent employment has increased significantly in the last two decades. Not much is known about the impact of this shift on disparities in access to health insurance and other benefits. I examined disparities in access to any type of health insurance, employer-sponsored health insurance and workers’ compensation (WC) benefits between contingent and non-contingent workers in U.S. agriculture. I used the National Agricultural Workers Survey and the extended Oaxaca-Blinder decomposition technique to estimate disparities. Contingent employment could be a barrier to access of health insurance and WC benefit, which in turn could contribute to health inequalities in the long-run

The Limits of an Egalitarian Ethos: G. A. Cohen's Critique of Rawlsian Liberalism

G.A. Cohen’s critique of the Rawlsian difference principle points out an inconsistency in its presentation. The initial equality decided by the participants in the original position under the veil of ignorance is not preserved by the inequality sanctioned by the difference principle. Cohen shows how the breakdown of the initial equality of the original position prevents the desired results of the Rawlsian system from being realized. Cohen argues that an egalitarian ethos is required within a society for equality preserving economic distributions and Pareto superior outcomes to occur. Nonetheless, Cohen’s analysis of Rawls misses the ultimate cause of inequality, which is the dynamics of capital accumulation. An egalitarian ethos is only possible if there is a socialist mode of production to facilitate its development. Additionally, Cohen’s critique of Rawlsian constructivism through an argument for intuitionism does not address the natural-material existence of human beings. This existence must be considered for any advantageous social formation

U.S. Government Manual 2008-2009 Edition: Social Security Administration

[Excerpt] The Social Security Administration manages the Nation’s social insurance program—consisting of retirement, survivors, and disability insurance programs—commonly known as Social Security. It also administers the Supplemental Security Income program for the aged, blind, and disabled. The Administration is responsible for studying the problems of poverty and economic insecurity among Americans and making recommendations on effective methods for solving these problems through social insurance. The Administration also assigns Social Security numbers to U.S. citizens and maintains earnings records for workers under their Social Security numbers

Mortality Change, the Uncertainty Effect, and Retirement

We examine the role of changing mortality in explaining the rise of retirement over the course of the 20th century. We construct a model in which individuals make labor/leisure choices over their lifetimes subject to uncertainty about their date of death. In an environment in which mortality is high, an individual who saved up for retirement would face a high risk of dying before he could enjoy his planned leisure. In this case, the optimal plan is for people to work until they die. As mortality falls, however, it becomes optimal to plan, and save for, retirement. We simulate our model using actual changes in the US life table over the last century, and show that this 'uncertainty effect' of declining mortality would have more than outweighed the 'horizon effect' by which rising life expectancy would have led to later retirement. One of our key results is that continuous changes in mortality can lead to discontinuous changes in retirement behavior.

Unchecked: How Wal-Mart Uses its Might to Block Port Security

[Excerpt] In spite of the vulnerability of our ports and of supply networks around the world, Wal-Mart and RILA have—time and again since the attacks of Sept. 11, 2001—opposed new maritime and port security rules. Their mantra is: “Security requirements should not become a barrier to trade.” The AFL-CIO’s unions represent millions of port, transportation and emergency workers including first responders, whose lives are on the line in the event of a catastrophic attack on America‘s ports. This report details the ways in which Wal-Mart’s lobbyists and allies have quietly and insistently made these workers and all Americans less safe