Measures of Desirability Beliefs and their Validity as Indicators for Socially Desirable Responding

Social desirability (SD)-bias is a serious threat for survey-data quality, and the respondents’ desirability beliefs have proven in many studies to predict the incentives for the strength as well as for the direction of this bias. However, the issue of the relative validity of different ways to measure these incentives has hardly received any attention. We introduced three such measures and discussed the respective tradeoffs between their parsimony on the one hand and the implied assumptions which have to be fulfilled on the other. In the empirical part of our paper, we tested with four questionnaire topics whether and how strong these assumptions are violated and thus how much measurement effort is necessary to obtain a sufficiently good indicator for the perceived incentives for SD-bias. These topics were: (a) having prejudice against the elderly, (b) making charitable donations, (c) participating in political elections and (d) being environmentally conscious. We found the most parsimonious one-point measure to be strongly affected by measurement error in the case of all questionnaire topics. Depending on how strong the assumption of monotony was violated, for some topics the medium elaborated simple difference scores were sufficiently valid, but partly only the most elaborated domain-specific difference scores were a valid predictor for the potential strength and direction of incentives for SD-bias.

How to Work with Honest but Curious Judges? (Preliminary Report)

The three-judges protocol, recently advocated by Mclver and Morgan as an example of stepwise refinement of security protocols, studies how to securely compute the majority function to reach a final verdict without revealing each individual judge's decision. We extend their protocol in two different ways for an arbitrary number of 2n+1 judges. The first generalisation is inherently centralised, in the sense that it requires a judge as a leader who collects information from others, computes the majority function, and announces the final result. A different approach can be obtained by slightly modifying the well-known dining cryptographers protocol, however it reveals the number of votes rather than the final verdict. We define a notion of conditional anonymity in order to analyse these two solutions. Both of them have been checked in the model checker MCMAS

Distributed Exploration in Multi-Armed Bandits

We study exploration in Multi-Armed Bandits in a setting where $k$ players collaborate in order to identify an $\epsilon$-optimal arm. Our motivation comes from recent employment of bandit algorithms in computationally intensive, large-scale applications. Our results demonstrate a non-trivial tradeoff between the number of arm pulls required by each of the players, and the amount of communication between them. In particular, our main result shows that by allowing the $k$ players to communicate only once, they are able to learn $\sqrt{k}$ times faster than a single player. That is, distributing learning to $k$ players gives rise to a factor $\sqrt{k}$ parallel speed-up. We complement this result with a lower bound showing this is in general the best possible. On the other extreme, we present an algorithm that achieves the ideal factor $k$ speed-up in learning performance, with communication only logarithmic in $1/\epsilon$

The Use of Marketing Knowledge in Formulating and Enforcing Consumer Protection Policy

The purpose of this first chapter of the handbook is to discuss how the findings and approaches offered by the marketing discipline are used in consumer protection policy

Trumping the First Amendment?

The primary goal of this Essay is to assess whether the relationship between the ideology of Supreme Court Justices and their support for the First Amendment guarantees of speech, press, assembly, and association has declined, such that left-of-center Justices no longer consistently support those guarantees, and right-of-center Justices no longer consistently support their regulation. Utilizing data drawn from the 1953 through 2004 terms of the Court, we show that, in disputes in which only First Amendment claims are at issue, the more liberal the Justice, the higher the likelihood that he or she will vote in favor of litigants alleging an abridgment of their rights. That relationship, however, fails to emerge in disputes in which other values, such as privacy and equality, are also prominently at stake. In these cases, liberal Justices are no more likely than their conservative counterparts to support the First Amendment; indeed, if anything, a reversal of sorts occurs, with conservatives more likely, and liberals less likely, to vote in favor of the speech, press, assembly, or association claim. Taken collectively, these results indicate that commitment to First Amendment values is no longer a lodestar of liberalism. We consider the implications of these findings in light of long-held assumptions of (quantitative) political science work on the Court

Probable innocence in the presence of independent knowledge

We analyse the Crowds anonymity protocol under the novel assumption that the attacker has independent knowledge on behavioural patterns of individual users. Under such conditions we study, reformulate and extend Reiter and Rubin's notion of probable innocence, and provide a new formalisation for it based on the concept of protocol vulnerability. Accordingly, we establish new formal relationships between protocol parameters and attackers' knowledge expressing necessary and sufficient conditions to ensure probable innocence