Estimation of the characteristics of a Lévy process

We consider a Lévy process that is e.g. used in finance to model stock price developments. We want to estimate the characteristics of that process, based on historical data where we assume that we have discrete, high frequency observations. We introduce a threshold estimation method and show consistency and in the case of finite activity asymptotic normality of these estimators.     

Mythos Flexibilisierung?

In this article, we address the current debate of increasing work life flexibility in (West-) Germany. In order to shed some light on the contradiction between a widely accepted decrease in work life stability and empirical findings that do not confirm such a decline, we contrast “objective” evidence from occupational trajectories with “subjective” evidence on various dimensions of perceived continuity and discontinuity of job histories. We use the West German part of the German Life History Study for a survival analysis of occupational mobility for cohorts born between 1929 and 1971. Here, using a new concept, we distinguish between direct mobility and indirect mobility which is defined as an occupational change that happens after an employment interruption. In addition, we analyze a new German cross-sectional data set from 2005 on retrospective career perceptions. We employ multinomial regression models to understand whether younger individuals report more unwanted occupational mobility and employment interruptions than older individuals. Our findings indicate that direct occupational mobility has neither increased across cohorts nor has it surged upward for the most recent cohorts, but that there has been an increase in indirect occupational mobility. Furthermore, while there is no higher incidence of unwanted occupational mobility in younger age groups, we find mixed evidence regarding the increased occurrence of unwanted career interruptions in younger age groups. Finally, the desire to experience occupational and firm changes has grown for younger age groups.     

Acculturation and Prejudice in Germany: Majority and Minority Perspectives

This article explores the connections between prejudice and specific attitudes toward acculturation in Germany. Results of surveys confirm the hypothesis that prejudice is related to ideologies of assimilation and segregation among majority- group members. Moreover, experimental and correlational studies indicate that these attitudes are linked to discriminatory behavior. Further analyses of studies with ethnic minorities prove that prejudice and acculturation are linked within minority groups as well. Additionally it is shown that prejudice is functional in order for minorities to acculturate. These studies confirm the impression that there is a close link between macrosocial and microsocial levels of coping with migration.     

Beyond Make‐Buy: Internalization and Integration of Design and Production

Much recent attention in industrial practice has been centered on the question of which activities a manufacturing firm should complete for itself and for which it should rely on outside suppliers. This issue, generally labeled the “make‐buy” decision, has received substantial theoretical and empirical attention. In this paper, we broaden the scope of the make‐buy decision to include product design decisions, as well as production decisions. First, we examine independently the decisions of whether to internalize design and production, and then we consider how design and production organizational decisions are interdependent. The specific research questions we address are: (1) How can design and production sourcing decisions be described in richer terms than “make” and “buy”? (2) Do existing theories of vertical integration apply to product design activities as well as production decisions? (3) What is the relationship between the organization of design and the organization of production? (4) What organizational forms for design and production are seen in practice? After developing theoretical arguments and a conceptual framework, we explore these ideas empirically through an analysis of design and production sourcing decisions for bicycle frames in the U. S. mountain bicycle industry.     

DOES PUBLIC ATTENTION REDUCE THE INFLUENCE OF MONEYED INTERESTS? POLICY POSITIONS ON SOPA/PIPA BEFORE AND AFTER THE INTERNET BLACKOUT

We investigate the role of public attention in determining the effect that campaign contributions by interest groups have on legislators' policy positions. We exploit the shock in public attention induced by the Internet service blackout of January 2012 that increased the salience of the Stop Online Piracy Act/Protect IP Act (SOPA/PIPA) bills aimed at stronger protection of property rights on the Internet. Using a new dataset of U.S. congressmen's public statements, we find a strong statistical relationship between campaign contributions funded by the affected industries and legislators' positions. However, this relationship evaporates once the two bills become primary policy issues. Our results are consistent with the notion that legislators choose positions on secondary policy issues in order to cater to organized interests, whereas positions on primary policy issues are driven by electoral support. (JEL D72, L82, L86)     

Masses,Crowds, Communities,Movements: Collective Action in the Internet Age

This article investigates two questions: One, how might the very differently structured social collectives on the Internet – masses, crowds, communities and movements – be classified and distinguished? And two, what influence do the technological infrastructures in which they operate have on their formation, structure, and activities? For this, we differentiate between two main types of social collectives: non-organized collectives, which exhibit loosely coupled collective behavior, and collective actors with a separate identity and strategic capability. Further, we examine the newness, or distinctive traits, of online-based collectives, which we identify as being the strong and hitherto non-existent interplay between the technological infrastructures that these collectives are embedded in and the social processes of coordination and institutionalization they must engage in, in order to maintain their viability over time. Conventional patterns of social dynamics in the development and stabilization of collective action are now systematically intertwined with technology-induced processes of structuration.     

Vorwort

Although the concept of tie strength plausibly extends opinion leadership theory, prior studies have indicated that tie strength is of minor importance for opinion leadership. The paper argues that strong ties and weak ties play major roles in the process of opinion leadership that prior studies have insufficiently differentiated due to methodological limitations. Against this background, a methodologically more rigorous reassessment of the association between tie strength and opinion leadership is conducted. The reassessment centers on the combination of ego-centered network analyses with statistical methods of multilevel analysis. These are applied to original data of a study by Schenk (2006) on financial opinion leadership in Germany (n?=?10,100 survey respondents) which has previously been considered as an important indication for tie strength’s minor importance. Empirical results show that strong ties and weak ties are remarkably more important in the process of opinion leadership than previously known. Opinion leaders benefit from strong ties, because personal influence can be carried through them comparatively easily. By contrast, weak ties foster opinion leadership in a structural manner by catalyzing the influence that opinion leaders can exert through strong ties.     

Finanzialisierung,Demokratie und Gesellschaft – zehn Jahre nach Beginn der Finanzkrise

This introduction to the special issue—ten years after the collapse of the investment bank Lehman Brothers and the beginning of a worldwide financial, economic, and debt crisis—reflects on the extent to which the economic crisis affected a turning point in society overall. The current state of research into the relationship between financialization, democracy, and social conditions strongly suggests that while the processes of financialization that favored the emergence of a crisis were influenced by the financial crisis, they were not completely reversed. In fact, the financial market regulation, which was changed in response to the crisis, did not exert any modifying pressure in terms of a restructuring of the financial system. An epochal shift in financial market regulation therefore cannot be identified from the steps taken in the reform process. Elseways there is clear evidence that the financial crisis has had a lasting impact on the European integration process, confidence in democracy, and political culture. The financial crisis is therefore likely to be perceived as a historical watershed, mainly due to its impact on societal areas beyond the financial system itself.     

Consistent and rate-optimal density estimation from heteroscedastic data groups

We consider the problem of estimating a density function based on aggregated data where the data group sizes may differ from each other. The reconstruction of the target density can be regarded as a nonlinear statistical inverse problem. We introduce some estimation procedures which are capable to use the observations from all groups by some nonstandard deconvolution techniques. General consistency and rate-optimality under common smoothness constraints are developed. We give some numerical simulations and a data-driven bandwidth selector.