11 research outputs found
Incentives and Efficiency in Uncertain Collaborative Environments
We consider collaborative systems where users make contributions across
multiple available projects and are rewarded for their contributions in
individual projects according to a local sharing of the value produced. This
serves as a model of online social computing systems such as online Q&A forums
and of credit sharing in scientific co-authorship settings. We show that the
maximum feasible produced value can be well approximated by simple local
sharing rules where users are approximately rewarded in proportion to their
marginal contributions and that this holds even under incomplete information
about the player's abilities and effort constraints. For natural instances we
show almost 95% optimality at equilibrium. When players incur a cost for their
effort, we identify a threshold phenomenon: the efficiency is a constant
fraction of the optimal when the cost is strictly convex and decreases with the
number of players if the cost is linear
Social Status and Badge Design
Many websites rely on user-generated content to provide value to consumers.
These websites typically incentivize participation by awarding users badges
based on their contributions. While these badges typically have no explicit
value, they act as symbols of social status within a community. In this paper,
we consider the design of badge mechanisms for the objective of maximizing the
total contributions made to a website. Users exert costly effort to make
contributions and, in return, are awarded with badges. A badge is only valued
to the extent that it signals social status and thus badge valuations are
determined endogenously by the number of users who earn each badge. The goal of
this paper is to study the design of optimal and approximately badge mechanisms
under these status valuations. We characterize badge mechanisms by whether they
use a coarse partitioning scheme, i.e. awarding the same badge to many users,
or use a fine partitioning scheme, i.e. awarding a unique badge to most users.
We find that the optimal mechanism uses both fine partitioning and coarse
partitioning. When status valuations exhibit a decreasing marginal value
property, we prove that coarse partitioning is a necessary feature of any
approximately optimal mechanism. Conversely, when status valuations exhibit an
increasing marginal value property, we prove that fine partitioning is
necessary for approximate optimality
Behavioral Mechanism Design: Optimal Contests for Simple Agents
Incentives are more likely to elicit desired outcomes when they are designed
based on accurate models of agents' strategic behavior. A growing literature,
however, suggests that people do not quite behave like standard economic agents
in a variety of environments, both online and offline. What consequences might
such differences have for the optimal design of mechanisms in these
environments? In this paper, we explore this question in the context of optimal
contest design for simple agents---agents who strategically reason about
whether or not to participate in a system, but not about the input they provide
to it. Specifically, consider a contest where potential contestants with
types each choose between participating and producing a submission
of quality at cost , versus not participating at all, to maximize
their utilities. How should a principal distribute a total prize amongst
the ranks to maximize some increasing function of the qualities of elicited
submissions in a contest with such simple agents?
We first solve the optimal contest design problem for settings with
homogenous participation costs . Here, the optimal contest is always a
simple contest, awarding equal prizes to the top contestants for a
suitable choice of . (In comparable models with strategic effort choices,
the optimal contest is either a winner-take-all contest or awards possibly
unequal prizes, depending on the curvature of agents' effort cost functions.)
We next address the general case with heterogeneous costs where agents' types
are inherently two-dimensional, significantly complicating equilibrium
analysis. Our main result here is that the winner-take-all contest is a
3-approximation of the optimal contest when the principal's objective is to
maximize the quality of the best elicited contribution.Comment: This is the full version of a paper in the ACM Conference on
Economics and Computation (ACM-EC), 201
Rating mechanisms for sustainability of crowdsourcing platforms
Crowdsourcing leverages the diverse skill sets of large collections of individual contributors to solve problems and execute projects, where contributors may vary significantly in experience, expertise, and interest in completing tasks. Hence, to ensure the satisfaction of its task requesters, most existing crowdsourcing platforms focus primarily on supervising contributors\u27 behavior. This lopsided approach to supervision negatively impacts contributor engagement and platform sustainability
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The Cost of Sharing Information in a Social World
With the increasing prevalence of large scale online social networks, the field has evolved from studying small scale networks and interactions to massive ones that encompass huge fractions of the world’s population. While many methods focus on techniques at scale applied to a single domain, methods that apply techniques across multiple domains are becoming increasingly important. These methods rely on understanding the complex relationships in the data. In the context of social networks, the big data available allows us to better model and analyze the flow of information within the network.
The first part of this thesis discusses methods to more effectively learn and predict in a social network by leveraging information across multiple domains and types of data. We document a method to identify users from their access to content in a network and their click behavior. Even on a macro level, click behavior is often hard to obtain. We describe a technique to predict click behavior using other public information about the social network.
Communication within a network inevitably has some bias that can be attributed to individual preferences and quality as well as the underlying structure of the network. The second part of the thesis characterizes the structural bias in a network by modeling the underlying information flow as a commodity of trade
Essays In Algorithmic Market Design Under Social Constraints
Rapid technological advances over the past few decades---in particular, the rise of the internet---has significantly reshaped and expanded the meaning of our everyday social activities, including our interactions with our social circle, the media, and our political and economic activities
This dissertation aims to tackle some of the unique societal challenges underlying the design of automated online platforms that interact with people and organizations---namely, those imposed by legal, ethical, and strategic considerations.
I narrow down attention to fairness considerations, learning with repeated trials, and competition for market share. In each case, I investigate the broad issue in a particular context (i.e. online market), and present the solution my research offers to the problem in that application.
Addressing interdisciplinary problems, such as the ones in this dissertation, requires drawing ideas and techniques from various disciplines, including theoretical computer science, microeconomics, and applied statistics.
The research presented here utilizes a combination of theoretical and data analysis tools to shed light on some of the key challenges in designing algorithms for today\u27s online markets, including crowdsourcing and labor markets, online advertising, and social networks among others