Browsing by Author "Engel, Ofer"

Now showing 1 - 6 of 6
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    Close communications: Hedge funds, brokers and the emergence of herding
    (British Journal of Management, 2016-03-09) Kellard, N.; Millo, Y.; Simon, J.; Engel, Ofer
    We examine how communication, evaluation and decision-making practices among competing market actors contribute to the establishment of herding and whether this has impact on market wide phenomena such as prices and risk. Data is collected from interviews and observations with hedge fund industry participants in Europe, the United States and Asia. We examine both contemporaneous and biographical data, finding that decision making relies on an elaborate two-tiered structure of connections among hedge fund managers and between them and brokers. This structure is underpinned by idea sharing and development between competing hedge funds leading to ‘expertisebased’ herding and an increased probability of over-embeddedness. We subsequently present a case study demonstrating the role that communication between competing hedge funds plays in the creation of herding and show that such trades affect prices by introducing an additional risk: the disregarding of information from sources outside the trusted connections.
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    The Coleman Diagram, Small N Inquiry and Ethnographic Causality
    (Sociologica, Italian journal of sociology, 2018-12-14) Abell, Peter; Engel, Ofer
    Certain key ideas have served to stimulate thought about the nature of sociological inquiry by presenting frameworks which are adjustable to the varying demands of different sorts of data. They provide, as it were, heuristics which enable a systematic debate about the optimal simplifications that are enjoined by varying types of data, notably what are sometimes labelled as quantitative and qualitative. In so doing they facilitate a variety of analyses, generate hypotheses and eventually lead to discoveries that transcend inherited boundaries. Our claim is that the Coleman diagram, though largely interpreted within a quantitative tradition, is one such framework for formalizing qualitative methods and for understanding the interplay between different types of data in the social sciences
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    Corporate Social Responsibility, Inequality and Corporate Governance
    (Palgrave Macmillan, 2015) Abell, Peter; Engel, Ofer; Wynn, Henry
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    The influence of structural balance and homophily/heterophobia on the adjustment of random complete signed networks
    (Elsevier, 2015-09-25) Deng, Hongzhong; Abell, Peter; Engel, Ofer; Wu, Jun; Tan, Yuejin
    Inconsistencies in the empirical support for balance theory are often explained by recourse to competing mechanisms that reduce the total degree of balance in the network. These mechanisms (such as differential popularity and subgroup hostility) may depend on exogenous properties of the nodes. This paper offers an alternative explanation for the departure of networks from global balance, according to which the myopic nature of sign adjustment in accordance with a pressure for local balance may reduce the global degree of balance and impede the formation of groups, whereas competing mechanisms that rely on exogenous node properties (e.g., homophily) facilitate these processes. The paper describes a set of simulations designed to study the evolution of complete signed networks under a local sign-change regime, induced by structural balance, homophily and heterophobia. Tolerance for local violation of balance and homophily is allowed to vary with a consequent impact upon the global degree of balance and group formation processes. We find the conditions under which the pressure towards local homophily and balance operate against each other culminating in a (locally) dynamic yet (globally) stationary state in which homophily adjusts towards group formation and balance undermines this process
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    Sentiment Analysis using TF-IDF Weighting of UK MPs’ Tweets on Brexit
    (Elsevier, 2021-06-17) Mee, Alexander; Homapour, Elmina; Chiclana, Francisco; Engel, Ofer
    The past decade saw remarkable growth in the production of user-generated text data due to ever-increasing usage of social media. During the same time Twitter has become an indispensable communication tool for politicians. To explore this link, we examine what usage patterns reveal about users’ opinions on the issue of Brexit, these usage patterns consisting of tweet frequency and length, as well as the terms used and their length. We analyse 185,970 tweets from 576 twitter accounts, each account associated with a Member of the British Parliament (MP). We use regression analysis and sentiment analysis, namely Term Frequency–Inverse Document Frequency (TF–IDF), to investigate if there is a relationship between the features of text data and the characteristics of Twitter users. Whereas these methods have previously been applied to American two-party politics, the multiple parties of the British political landscape have led to previous studies using typological analysis (human classifiers) to identify tweets. We present a methodology that assigns a political value based on an MP’s voting record on a single issue (Brexit). We identify systematic yet subtle differences in the way the two sides of the debate use language, but also specific usage patterns that are common to both.
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    Subjective Causality and Counterfactuals in the Social Sciences
    (Sage, 2019-11-12) Abell, Peter; Engel, Ofer
    The article explores the role that subjective evidence of causality and associated counterfactuals and counterpotentials might play in the social sciences where comparative cases are scarce. This scarcity rules out statistical inference based upon frequencies and usually invites in-depth ethnographic studies. Thus, if causality is to be preserved in such situations, a conception of ethnographic causal inference is required. Ethnographic causality inverts the standard statistical concept of causal explanation in observational studies, whereby comparison and generalization, across a sample of cases, are both necessary prerequisites for any causal inference. Ethnographic causality allows, in contrast, for causal explanation prior to any subsequent comparison or generalization.