Scott L. Feld

The Focused Organization of Social Ties

Sociologists since Simmel have been interseted in social circles as essential features of friendship networks. Although network analysis has been increasingly used to uncover patterns among social relationships, theoretical explanations of these patterns have been inadequate. This paper presents a theory of the social organization of friendship ties. The approach is based upon Homanss concepts of activities, interactions, and sentiments and upon the concept of extra-network foci organizing social activities and interaction. The theory is contrasted with Heiders balance theory. Implications for transitivity, network bridges, and density of personal networks are discussed and presented as propositions. The focus theory is whosn to help explain patterns of friendships in the 1965-66 Detroit Area Study. This paper is intended as a step toward the development of integrated theory to explain interrelationships between networks and other aspects of social structure. Inplications for data analysis are discussed.

Thirteen theorems in search of the truth

We review recent work on the accuracy of group judgmental processes as a function of (a) the competences (judgmental accuracies) of individual group members, (b) the group decision procedure, and (c) group size. This work on individual competence and group accuracy represents an important contribution to democratic theory and a useful complement to the usual emphasis in the social choice literature on individual preference and preference aggregation mechanisms. The work reported on is rooted in a tradition which goes back to scholars such as Condorcet, Poisson, and Bayes.

Detecting measurement bias in respondent reports of personal networks

Inaccuracy of sociometric reports poses a serious challenge to social network analysis. Nevertheless, researchers continue to draw potentially misleading conclusions from flawed data. We consider two particular types of systematic error in measurement of network size: individuals over/underreporting others (expansiveness bias), and individuals being over/underreported by others (attractiveness bias). We examine evidence of individual variation in these biases in one apparently typical sociometric dataset. We specifically suggest that variation in expansiveness bias may commonly distort findings concerning characteristics of individual networks (e.g. size, range, density), and properties of whole networks (e.g. inequality, transitivity, clustering, and blockmodels). We suggest methodological improvements and urge further research.

Collective decision making : an economic outlook

This book provides an economic approach to the study of collective decision making. In Social Choice theory, the main problem of collective decision making is normally conceived of as one of aggregating diverse individual preferences. However, in practice, objectives are often common to the individuals - whether, for instance, in the firm, or where a medical diagnosis is required - but the information available to each individual, and their ability to utilise that information optimally, differ. The authors therefore deal with a different problem of decisional skills aggregation assuming homogeneous preferences but differing decisional skills, and develop a framework for the study of collective decision making. They examine the effect of the size of the decision making body; incomplete information on decisional skills; interdependence among decisions; shadow prices of decision rules; and of decision making costs and benefits on optimal group decision making. The model is then illustrated in a range of different fields, including industrial organisation, labour economics and in the design of consulting schemes, medical diagnostic systems, and corporate law.

PROVING A DISTRIBUTION-FREE GENERALIZATION OF THE CONDORCET JURY THEOREM*

Abstract We provide a proof for a result due to Grofman, Owen and Feld (1982), a distribution-free generalization of the Condorcet Jury Theorem (1785). In proving this result we show exactly what distribution of individual competence maximizes/minimizes the judgmental accuracy of group majority decision processes.

Describing Changes in Personal Networks over Time

Social ties are continuously being created and lost as well as changing their nature over time. We emphasize that network descriptions are specific to their particular definitions of ties. Then, we suggest that studies of change can focus on: (1) individual ties, or whole personal networks; and (2) whether ties are gained or lost, or change their characteristics over time. For each of four possible study types, we describe an ideal type, provide a concrete empirical example, and briefly describe illustrative published work. Particular networks can rarely be regarded as random samples of meaningful populations, and generalization to populations of networks requires often challenging theoretical considerations of the nature of the relevant populations, as well as statistical considerations of random sampling error. Nevertheless, systematic description of changes within particular networks provides the bases for more general understanding of processes and outcomes of changes of social networks over time.

THE CORE AND THE STABILITY OF GROUP CHOICE IN SPATIAL VOTING GAMES

l he core of a voting game is the set of undominated outcomes, that is, those that once in place cannot be overturned. For spatial voting games, a core is structurally stable if it remains in existence even if there are small perturbations in the location of voter ideal points. While for simple majority rule a core will exist in games with more than one dimension only under extremely restrictive symmetry conditions, we show that, for certain supramajorities, a core must exist. We also provide conditions under which it is possible to construct a structurally stable core. If there are only a few dimensions, our results demonstrate the stability properties of such frequently used rules as two-thirds and three-fourths. We further explore the implications of our results for the nature of political stability by looking at outcomes in experimental spatial voting games and at Belgian cabinet formation in the late 1970s.

Ideological Consistency as a Collective Phenomenon

Researchers ordinarily consider ideological consistency to be a characteristic of individuals; groups are considered to be ideological only if they are composed of ideologically oriented individuals. We show how a group as a whole can be characterized as exhibiting an ideological basis for its preferences even though many, or even most, of its members have preferences that are inconsistent with the supposed unidimensional ideological continuum. As an illustration, we show that the United States electorate of 1980 had collective preferences among the candidates Kennedy, Carter, Ford, and Reagan as if these preferences reflected an underlying left-right dimension among these candidates, despite the fact that a high proportion of individual voters had preferences among these candidates that did not fit the left-right dimension. In general, we show reasons why collectivities are likely to be more ideologically consistent than are the individuals composing them.

Democratic Theory and the Public Interest: Condorcet and Rousseau Revisited.

Bernard Grofman and Scott Feld argued in the June 1988 issue of this Review that Jean-Jacques Rousseaus contributions to democratic political theory could be illuminated by invoking the theorizing of one of his eighteenth-century contemporaries, the Marquis de Condorcet, about individual and collective preferences or judgments. Grofman and Felds claims about collective consciousness and the efficacy of the public interest provoke debate. One focus of discourse lies in the application of Condorcets jury theorem to Rousseaus theory of the general will. In this controversy David M. Estlund and Jeremy Waldron in turn raise a variety of issues of theory and interpretation; Grofman and Feld then extend their argument, and propose clarifications.

The uncovered set in spatial voting games

In a majority rule voting game, the uncovered set is the set of alternatives each of which can defeat every other alternative in the space either directly or indirectly at one remove. Research has suggested that outcomes under most reasonable agenda processes (both sincere and sophisticated) will be confined to the uncovered set. Most research on the uncovered set has been done in the context of voting games with a finite number of alternatives and relatively little is known about the properties of the uncovered set in spatial voting games.We examine the geometry of the uncovered set in spatial voting games and the geometry of two important subsets of the uncovered set, the Banks set and the Schattschneider set. In particular, we find both general upper and lower limits on the size of the uncovered set, and we give the exact bounds of the uncovered set for situations with three voters. For situations with three voters, we show that the Banks set is identical to the uncovered set.