seminar participants at the Columbia and University of Chicago business schools for guidance and feedback. We take full responsibility for remaining errors. Robust Identities or Non-Entities?Typecasting in the Feature Film Labor Market AbstractWe provide a framework for reconciling two seemingly incompatible claims regarding identity in social and economic arenas: (a) that complex, multivalent identities are advantageous because they afford greater flexibility; and (b) that simple, generic identities are advantageous because they facilitate interpretation by key audiences. Following Faulkner (1983), we argue that these claims do not conflict with one another but that they apply to different contexts. A generic identity is helpful in gaining the recognition necessary for sustained participation in a social arena. However, as one becomes better established, the limitations entailed by a simple, "typecast" identity increasingly rival the benefits. We test these hypotheses in an analysis of the labor market for actors in the feature film industry. Interviews with key informants and analysis of comprehensive data from the Internet Movie Database support the proposed theoretical framework. In addition, the evidence supports the salience of the hypothesized typecasting processes even in the presence of related processes based on underlying skill differences and social networks. Our results have important implications for research on identity formation in various social arenas, categorical boundaries in external labor markets, and more generally, the interplay between actor and position inherent in market dynamics. Robust Identities or Non-Entities?

Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ANAND SWAMINATHAN University of California at DavisWe introduce the construct of network inertia, referring to a persistent organizational resistance to changing interorganizational network ties or difficulties that an organization faces when it attempts to dissolve old relationships and form new network ties. Previous research has neglected the process of network change in favor of an emphasis on identifying beneficial content effects of networks. We emphasize the constraints on network change and propose a multilevel conceptual model relating key sources of network inertia to changes in network ties. We also discuss the implications of network inertia for the evolution of networks.

Additional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details.

No abstract

The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Although the niche figures prominently in contemporary theories of organization, analysts often fail to tie micro processes within the niche to long-term changes in the broader environment. In this paper, we advance arguments about the relationship between an organization's niche and evolution in the structure of its organizational population over time. We focus on the technological niche and processes of positioning and crowding among firms in the niche space, relating them to the level of concentration among all firms in the market. Building on previous empirical studies in organizational ecology, we study the evolution of concentration in the American automobile industry from 1885 to 1981 and estimate models of the hazard of exit of individual producers from the market. The findings show that niche and concentration interact in complex ways, yielding a more unified depiction of organizational evolution than typically described or reported.*Many analysts' accounts of the U,S-automobile industry's development, including conjectured reasons for particular firms succeeding and failing, can be readily interpreted from the perspective of the organizational niche. For instance, General Motors' historical success against Ford is hailed by many as the consequence of its early wide-ranging muitiproduct market position-a broad niche, in ecological terms. In more recent years, the Japanese manufacturers showed that they could build a sizeable presence after entering the market with small low-cost cars, a part of the market in which major American producers were not very competitive. According to a niche interpretation, one would say that the Japanese firms benefited from initial niche positions with little overlap from existing firms, allowing them to gain strength before attempting more direct competition.In the background of such niche-based processes, the competitive dynamics of the automobile industry have been driven by both cost and innovation, each of which is tied to scale. The scale of automobile production has increased steadily over the last century, and the race to remain competitively large often constitutes a main reason why automobile firms behave as they do. For instance, insider accounts of the recent round of mergers among large automakers, such as Chrysler and Daimler, point to the increasing scale of the global industry as the critical motivation (Vlasic and Stertz, 2000), As a result of this scale orientation, the automobile industry is characterized generally by a long-term...

The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. AbstractWe examine how experiential learning affects organizational change and its consequences on firm mortality. We develop hypotheses about the interactions of experiences with a specific type of organizational change on the one hand, and environmental stability, organizational size, and organizational niche width on the other hand. Our findings draw from analysis of the U.S. automobile industry between 1885 and 1981 and support the general prediction that "process" effects of change in the organizational core elevate the hazard of failure. We also find that a dynamic interpretation of organizational environments as comprised of other organizations helps to explicate the interplay between organization and environmental forces that shape the occurrence and outcome of transformation.

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We develop a framework for defining the boundaries of within-population market segments, differentiated based on type and level of resources. Using this framework, we propose a theory of the moves between market segments of all firms in an organizational population across its evolution. Focusing on commensalistic interdependence within a segment, we adapt density dependence theory to predict that processes of mutualism and competition operate concurrently, even across high counts of density, and affect firms' propensity to desert their segment. Analyses of moves between market segments by firms in the U.S. auto industry between 1895 and 1981 confirm our predictions and suggest the operation of a basic ecological process that shapes the evolution of population structure.• Although market segmentation and partitioning are central to organizational ecology theory, research on the evolution of within-population segments is scant. The three received ecological theories that explain the evolution of structure within populations and industries-size-localized competition Freeman, 1977, 1989;Baum and Mezias, 1992), scale-based selection (Carroll and Swaminathan, 2000;Dobrev and Carroll, 2003), and resource partitioning (Carroll, 1985;Dobrev, 2000;Boone, Carroll, and van Witteloostuijn, 2002)-all do so with recourse to the differential replacement (founding and disbanding) of organizations occupying similar positions in market space. In resource partitioning, for example, competition among large-scale generalist firms reduces their number and leads to the birth of small specialist firms. Essential to resource partitioning is the distinction between a market-center segment and peripheral segments, differentiated based on the type and level of resources: generalists occupy the resource-abundant center, and specialists flourish on the less-copious but also less-crowded periphery. So organizational failures (in the center) and start-ups (on the periphery) explain the evolution of segmentation and partitioning within a market. But the specific boundaries of these segments and, more importantly, the shifts in these boundaries over time are never directly observed or measured in resource-partitioning studies. Inferences about the evolution of market segments (center and periphery) are thus largely metaphoric. With market segment boundaries undefined, the dynamics of organizational movements between market segments remain theoretically and empirically underdeveloped, as origin and destination states in transitions are also undefined. This omission is unfortunate, because theory predicting position moves in market space might go far in explaining the development of industry structure.Prior studies of the automobile industries in Europe and the U.S. have begun to analyze firms' (changes in) market position by using organizational niches (a firm's variance in resource utilization along relevant environmental dimensions) to measure a firm's position (defined as the midpoint of a firm's niche) in market space (defined as the aggregate...