Stability and Segregation in Group Formation

This paper presents a model of group formation based on the assumption that individuals prefer to associate with people similar to them. It is shown that, in general, if the number of groups that can be formed is bounded, then a stable partition of the society into groups may not exist. (A partition is defined as stable if none of the individuals would prefer be in a different group than the one he is in.) However, if individuals' characteristics are one-dimensional, then a stable partition always exists. We give sufficient conditions for stable partitions to be segregating (in the sense that, for example, low-characteristic individuals are in one group and high-characteristic ones are in another) and Pareto efficient. In addition, we propose a dynamic model of individual myopic behavior describing the evolution of group formation to an eventual stable, segregating, and Pareto efficient partition. Journal of Economic Literature Classification Numbers: C72, H41.     

The demand commitment bargaining and snowballing cooperation

Summary A multi-person bargaining model based on sequential demands is studied for coalitional games with increasing returns to scale for cooperation. We show that for such games the (subgame perfect) equilibrium behavior leads to a payoff distribution which approaches the Shapley value as the money unit approaches 0. Subgame consistency and strategic equilibria are the main tools used in the analysis. The model is then applied to study a problem of public good consumption.I wish to thank Reinhard Selten, who introduced me with the topic of non-cooperative coalition bargaining, for many constructive discussions. Al Roth's warm hospitality during the academic year 1990–1991, as well as many useful remarks are also gratefully acknowledged. Helpful discussions with Dieter Balkenborg, Tatsuro Ichiishi, Richard Mclean, Benny Moldovanu, Daniel Seidmann Avner Shaked are gratefully acknowledged as well. Part of this research was also supported by the Deutscheforschungsgemeinschaft SFB 303 at the University of Bonn.     

The Borda rule,Condorcet consistency and Condorcet stability

Summary. The Borda rule is known to be the least vulnerable scoring rule to Condorcet inconsistency, Saari (2000). Such inconsistency occurs when the Condorcet winner (the alternative which is preferred to any other alternative by a simple majority) is not selected by the Borda rule. This note exposes the relationship between the Borda rule and the Condorcet q-majority principle as well as the Condorcet q-majority voting rule. The main result establishes that the Borda rule is Condorcet q-majority consistent when where k is the number of alternatives. The second result establishes that is the minimal degree of majority decisiveness corresponding to the Borda rule under sincere voting. The same majority is required to ensure decisiveness under the Borda rule and to ensure that a q-rule (the generalized q-majority Condorcet rule) is a voting rule. Received: April 8, 2002; revised version: July 17, 2002 Correspondence to:S. Nitzan     

Values as determinants of motivation: Tourism and other career choices

Neuman, Yoram, Abraham Pizam and Arie Reichel, Values as Determinants of Motivation: Tourism and Other Career Choices. Annals of Tourism Research 1980, VII (3): 428–442. This study examined the predictive validity of work values in explaining motivational patterns of three groups of career preparation differing in their occupational specificity: Tourism/Hospitality, Management, and Liberal Arts. It was found that the higher the occupational specificity of a career preparation the higher is the predictive validity of work values in explaining work motivations. As predicted, the best relationships between values and motivation was found in the maximally specified occupation, namely: tourism/hospitality students, followed by management students with the liberal arts students — the most flexible occupational group — having the lowest relationship between values and motivation. The implications of the findings for employee selection and motivation prediction in the tourism/hospitality industry are discussed.     

On large games with bounded essential coalition sizes

We consider games in characteristic function form where the worth of a group of players depends on the numbers of players of each of a finite number of types in the group. The games have bounded essential coalition sizes: all gains to cooperation can be achieved by coalitions bounded in absolute size (although larger coalitions are permitted they cannot realize larger per-capita gains). We show that the utility function of the corresponding "limit" market, introduced in Wooders (1988, 1994a) , is piecewise linear. The piecewise linearity is used to show that for almost all limiting ratios of percentages of player-types, as the games increase in size (numbers of players), asymptotically the games have cores containing only one payoff, and this payoff is symmetric (treats players of the same type identically). We use this result to show that for almost all limiting ratios of percentages of player-types, Shapley values of sequences of growing games converge to the unique limiting payoff.     

Toward global checks and balances

The rapid growth and importance of intergovernmental coordination in the regulation of markets, transportation and communication, the environment, and national security poses numerous challenges for democratic accountability within participating states. Direct public participation in the intergovernmental regulatory bodies is generally modest or absent. Information regarding their deliberations is limited. And the multiple oversight mechanisms and supervisory processes that exist at the domestic level of developed democracies that can scrutinize intergovernmental regulatory decisions tend to be lacking. This lack of accountability raises legitimacy concerns, the most prominent of which is the fear executive branch officials will delegate controversial policy decisions to intergovernmental bodies in order to escape democratic deliberation. In this paper we survey the ways that different review venues (other international institutions and national courts) are attempting to cope with these accountability related issues: we argue that national courts may prove to be the most effective venue for promoting democratic accountability. This is not because they are more reliably representative of their domestic constituency or possess a more cosmopolitan perspective than the bodies whose decisions they are reviewing. Rather their relative advantage lies in: (1) the increasing acceptance on the part of domestic courts that inter-judicial coordination is a prerequisite for their continued ability to fulfill their judicial review function; and (2) the visibility that the decisions of these courts possess. Acting together these two forces have the potential to foster greater transparency and public deliberation than most rival venues.     

Parental background,educational attainments and returns to schooling and to marriage: the case of Israel

This paper investigates the effect of family background attainments and on returns to own and wife's schooling, for Jewish males Israel. Three dimensions of paternal background are referred to: father's education, the prestige of the father's occupation, and whether the father is of a western origin (an advantage in the western-oriented Israeli society). For each of these types of segmentation it is found that both the level of and the returns to own and wife's schooling (after some years of marriage) are higher for those coming from a more favourable background.

These empirical findings are consistent with an investment in schooling model in which differences in demand (productivity of own and wife's schooling) vary more than differences in supply of investment funds.     

Property appraisal in high-rises: A cooperative game theory approach

The construction of the higher stories in a building is utterly contingent upon the construction of the lower ones, while the construction of lower stories does not require the construction of the higher ones. This rationale underlies our adoption of a cooperative game theory methodology for examining the value of units based on the cost approach of land appraisal. Particularly, we propose the Shapley value solution to examine the allocation of the land and construction cost among the stories of the building. We explore the allocation mechanism and derive several closed-form properties by which the value pattern of stories in a building is rationalized. The proposed cost allocation may, among other things, generate values when comparable market prices are unobservable (consistent with the cost approach); may be used by courts in order to compute compensations in cases of disputes regarding expansions and redevelopments of existing structures among co-owners; and may determine the rent cost allocation in an organization with several profit centers located on different floors of a building.     

Ownership coordination in a channel: Incentives,returns, and negotiations

In many industries firms have to make quantity decisions before knowing the exact state of demand. In such cases, channel members have to decide which firm will own the units until demand uncertainty is resolved. The decision about who should retain ownership depends on the balance of benefit and risk to each member. Ownership, after all, is costly. Whichever member owns the units accepts the risk of loss if more units are produced than can be sold. But ownership also grants firms the flexibility to respond to demand once it becomes known by adjusting price. In this study, we analyze ownership decisions in distribution channels and how those decisions are affected by demand uncertainty. We model demand based on micro-modeling of consumer utility functions and capture demand uncertainty related to market size and price sensitivity. This study shows that as long as the degree of uncertainty about market size is intermediate, the retailer and the manufacturer both benefit when the manufacturer maintains ownership of the units. But when there is substantial uncertainty about market size, the retailer and the channel are better off if the retailer takes ownership but the manufacturer still prefers to maintain ownership. Thus, there is potential for channel conflict regarding ownership under high levels of uncertainty. We show that, using product returns, the manufacturer can achieve the same outcome under retailer ownership as under manufacturer ownership. This provides an additional new rationale for the prevalence of product returns. The first-best outcome (from the perspective of total channel profit), however, is under retailer ownership without product returns when uncertainty is high (i.e., product returns reduce the total channel profit). Negotiations between the manufacturer and the retailer can lead to the first-best outcome but only under quite restrictive constraints that include direct side payments by the retailer to the manufacturer and the retailer being pessimistic about its outside option (when an agreement cannot be reached) during the negotiation.     

Effectiveness and safety of betrixaban extended prophylaxis for venous thromboembolism compared with standard-duration prophylaxis intervention in acute medically ill patients: a systematic literature review and network meta-analysis

Abstract

Aims: To determine the clinical effectiveness and safety of venous thromboembolism (VTE) prophylaxis using US- and Europe-approved anticoagulants relative to extended-duration VTE prophylaxis with betrixaban. Low molecular weight heparins (LMWHs), unfractionated heparin (UFH), fondaparinux sodium and placebo were each compared to betrixaban, as standard-duration VTE prophylaxis for hospitalized, non-surgical patients with acute medical illness at risk of VTE.

Materials and methods: A systematic literature review was conducted up to June 2019 to identify randomized controlled trials (RCTs) of VTE prophylaxis in hospitalized, non-surgical patients with acute medical illness at risk of VTE. Studies that reported the occurrence of VTE events (including death) and, where possible, major bleeding, from treatment initiation to 20–50?days thereafter were retrieved and extracted. A Bayesian fixed effect network meta-analysis was used to estimate efficacy and safety of betrixaban compared with standard-duration VTE prophylaxis.

Results: Seven RCTs were analyzed which compared betrixaban, LMWHs, UFH, fondaparinux sodium, or placebo. There were significantly higher odds (median odds [95% credible interval]) of VTE with LMWHs (1.38 [1.12–1.70]), UFH (1.60 [1.05–2.46]), and placebo (2.37 [1.55–3.66]) compared with betrixaban. There were significantly higher odds of VTE-related death with placebo (7.76 [2.14–34.40]) compared with betrixaban. No significant differences were observed for the odds of major bleeding with all comparators, VTE-related death with any active standard-duration VTE prophylaxis, or of VTE with fondaparinux sodium, compared with betrixaban.

Limitations and conclusions: In this indirect comparison, betrixaban was shown to be an effective regimen with relative benefits compared with LMWHs and UFH. This indicates that betrixaban could reduce the burden of VTE in at-risk hospitalized patients with acute medical illness who need extended prophylaxis, though without direct comparative evidence, stronger conclusions cannot be drawn.