Proportional Approval Voting, Harmonic k-median, and Negative Association

We study a generic framework that provides a unified view on two important classes of problems: (i) extensions of the k-median problem where clients are interested in having multiple facilities in their vicinity (e.g., due to the fact that, with some small probability, the closest facility might be malfunctioning and so might not be available for using), and (ii) finding winners according to some appealing multiwinner election rules, i.e., election system aimed for choosing representatives bodies, such as parliaments, based on preferences of a population of voters over individual candidates. Each problem in our framework is associated with a vector of weights: we show that the approximability of the problem depends on structural properties of these vectors. We specifically focus on the harmonic sequence of weights, since it results in particularly appealing properties of the considered problem. In particular, the objective function interpreted in a multiwinner election setup reflects to the well-known Proportional Approval Voting (PAV) rule. Our main result is that, due to the specific (harmonic) structure of weights, the problem allows constant factor approximation. This is surprising since the problem can be interpreted as a variant of the k-median problem where we do not assume that the connection costs satisfy the triangle inequality. To the best of our knowledge this is the first constant factor approximation algorithm for a variant of k-median that does not require this assumption. The algorithm we propose is based on dependent rounding [Srinivasan, FOCS\u2701] applied to the solution of a natural LP-relaxation of the problem. The rounding process is well known to produce distributions over integral solutions satisfying Negative Correlation (NC), which is usually sufficient for the analysis of approximation guarantees offered by rounding procedures. In our analysis, however, we need to use the fact that the carefully implemented rounding process satisfies a stronger property, called Negative Association (NA), which allows us to apply standard concentration bounds for conditional random variables

Multi-Winner Voting with Approval Preferences

From fundamental concepts and results to recent advances in computational social choice, this open access book provides a thorough and in-depth look at multi-winner voting based on approval preferences. The main focus is on axiomatic analysis, algorithmic results and several applications that are relevant in artificial intelligence, computer science and elections of any kind. What is the best way to select a set of candidates for a shortlist, for an executive committee, or for product recommendations? Multi-winner voting is the process of selecting a fixed-size set of candidates based on the preferences expressed by the voters. A wide variety of decision processes in settings ranging from politics (parliamentary elections) to the design of modern computer applications (collaborative filtering, dynamic Q&A platforms, diversity in search results, etc.) share the problem of identifying a representative subset of alternatives. The study of multi-winner voting provides the principled analysis of this task. Approval-based committee voting rules (in short: ABC rules) are multi-winner voting rules particularly suitable for practical use. Their usability is founded on the straightforward form in which the voters can express preferences: voters simply have to differentiate between approved and disapproved candidates. Proposals for ABC rules are numerous, some dating back to the late 19th century while others have been introduced only very recently. This book explains and discusses these rules, highlighting their individual strengths and weaknesses. With the help of this book, the reader will be able to choose a suitable ABC voting rule in a principled fashion, participate in, and be up to date with the ongoing research on this topic

Multi-Winner Voting with Approval Preferences

Approval-based committee (ABC) rules are voting rules that output a fixed-size subset of candidates, a so-called committee. ABC rules select committees based on dichotomous preferences, i.e., a voter either approves or disapproves a candidate. This simple type of preferences makes ABC rules widely suitable for practical use. In this book, we summarize the current understanding of ABC rules from the viewpoint of computational social choice. The main focus is on axiomatic analysis, algorithmic results, and relevant applications.Comment: This is a draft of the upcoming book "Multi-Winner Voting with Approval Preferences

Some Statistical Models for Prediction

This dissertation examines the use of statistical models for prediction. Examples are drawn from public policy and chosen because they represent pressing problems facing U.S. governments at the local, state, and federal level. The first five chapters provide examples where the perfunctory use of linear models, the prediction tool of choice in government, failed to produce reasonable predictions. Methodological flaws are identified, and more accurate models are proposed that draw on advances in statistics, data science, and machine learning. Chapter 1 examines skyscraper construction, where the normality assumption is violated and extreme value analysis is more appropriate. Chapters 2 and 3 examine presidential approval and voting (a leading measure of civic participation), where the non-collinearity assumption is violated and an index model is more appropriate. Chapter 4 examines changes in temperature sensitivity due to global warming, where the linearity assumption is violated and a first-hitting-time model is more appropriate. Chapter 5 examines the crime rate, where the independence assumption is violated and a block model is more appropriate. The last chapter provides an example where simple linear regression was overlooked as providing a sensible solution. Chapter 6 examines traffic fatalities, where the linear assumption provides a better predictor than the more popular non-linear probability model, logistic regression. A theoretical connection is established between the linear probability model, the influence score, and the predictivity

Electronic voting : 6th International Joint Conference, E-Vote-ID 2021, virtual event, October 5-8, 2021

This book constitutes the proceedings of the 6th International Conference on Electronic Voting, E-Vote-ID 2021, held online -due to COVID -19- in Bregenz, Austria, in October 2021. The 14 full papers presented were carefully reviewed and selected from 55 submissions. The conference collected the most relevant debates on the development of Electronic Voting, from aspects relating to security and usability through to practical experiences and applications of voting systems, as well as legal, social or political aspects

A method for analysis of expert committee decision-making applied to FDA medical device panels

Thesis (Ph. D.)--Massachusetts Institute of Technology, Engineering Systems Division, 2010.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student submitted PDF version of thesis.Includes bibliographical references (p. 254-263).Committees of experts are critical for decision-making in engineering systems. This is because the complexity of these systems requires that information is pooled from across multiple specialties and domains of knowledge. The social elements of technical decision-making are not well understood, particularly among expert committees. This is largely due to a lack of methodology for directly studying such interactions in real-world situations. This thesis presents a method for the analysis of transcripts of expert committee meetings, with an eye towards understanding the process by which information is communicated in order to reach a decision. In particular, we focus on medical device advisory panels in the US Food and Drug Administration. The method is based upon natural language processing tools, and is designed to extract social networks in the form of directed graphs from the meeting transcripts which are representative of the flow of information and communication on the panel. Application of this method to a set of 37 meetings from the FDA's Circulatory Systems Devices Panel shows the presence of numerous effects. Prominent among these is the propensity for panel members from similar medical specialties to use similar language. Furthermore, panel members who use similar language tend to vote similarly. We find that these propensities are correlated - i.e., as panel members' language converges by medical specialty, panel members' votes also converge. This suggests that voting behavior is mediated by membership in a medical specialty and supports the notion that voting outcome is, to some extent, dependent on an interpretation of the data associated with training, particularly when a small number of interpretations of the data are possible. Furthermore, there is some preliminary evidence to suggest that as clinical trial data ambiguity and difficulty of decisionmaking increases, the strength of the mediating effect of medical specialty decreases. Assuming a common decision is reached, this might indicate that committee members are able to overcome their specialty perspective as the committee jointly deals with hard problems over longer periods of time. In cases where the panel's vote is split, a lack of linguistic coherence among members of the same medical specialty correlates with a lack of linguistic coherence among members who vote the same way. This could be due to the presence of multiple interpretations of the data, leading to idiosyncratic or value-based choice. We also find that voting outcome is associated with the order in which panel members ask questions - a sequence set by the committee chair. Members in the voting minority are more likely to ask questions later than are members in the voting majority. Voting minority members are also more likely to be graph sinks (i.e., nodes in a social network that have no outflow) than are voting majority members. This suggests an influence mechanism on these panels that might be associated with framing - i.e., later speakers seem to be less able to convince other panel members to discuss their topics of interest contributing to these members' minority status. These results may have some relation to FDA panel procedures and structure. Finally, we present a computational model that embodies a theory of panel voting procedures. Model results are compared to empirical results and implications are drawn for the design of expert committees and their associated procedures in engineering systems.by David André Broniatowski.Ph.D

A study of principals’ perceptions as implementers of Michigan’s mandated teacher evaluation policy

The purpose of this study was to identify and develop an understanding of the relationships between the perceptions of principals regarding the Michigan mandatory annual teacher evaluation policy and job satisfaction, self-efficacy, and stress as principals navigated the roles of building manager, instructional leader and policy implementer. This quantitative study asked 3,009 Michigan public school principals to share their perceptions regarding the teacher evaluation policy. A total of 426 principals responded to a questionnaire published in a web-based format using a Likert scale. Interest in this study by the Michigan Department of Education Research Department allowed access to all email addresses for Michigan public schools using the Educational Entity Master (EEM) system. Questions in the survey collected demographic data and uncovered perceptions held by respondents regarding policy implementation, role definition, and reinforced constructs of job satisfaction, self-efficacy, time, stress, need for training and fairness in the implementation process Stakeholder theory, which had roots in business, defined the reciprocal relationship between owners and stakeholders by observing management practices implemented for the pursuit of articulated organizational goals and served as the conceptual framework. Descriptive and inferential statistics were used for the analysis and showed Michigan principals were marginally knowledgeable regarding the requirements of the evaluation policy; job satisfaction and self-efficacy were correlated to principals’ voice in the formation and implementation of the evaluation policy especially at the building and district levels; a weak relationship existed between knowledge and respondent self-esteem; and the constructs of job satisfaction, self efficacy, stress/time and knowledge were predictors for successful vi implementation of the policy. Coding the open-ended question led to the reinforcement of themes pertaining to self-efficacy, job satisfaction, time and stress. Additional identified themes included the need for training and a concern for statewide level of fairness in completing the evaluation. Through the lens of stakeholder theory, it was important to acknowledge the reciprocal relationship between the principal (as stakeholder) and Michigan legislature (as the firm). To increase the knowledge, job satisfaction and self-efficacy of principals, the opportunity to provide a voice to policy formation and implementation is recommended. Professional organizations, government and educational agencies and higher education leadership programs must address communication and training opportunities for educational leaders