سرمایه اجتماعی در محل کار : مدارک و شواهد در شکل گیری و پیامدهای آن

The existence of social ties between co-workers affect many aspects of firm and worker behavior, such as how workers respond to a given set of incentives, the optimal compensation structures for workers at different tiers of the firm hierarchy, and the optimal organizational design for the firm. This paper presents evidence on the social capital in one particular firm, as embodied in the friendship ties among its workers. We describe the structure of the friendship network as a whole and present evidence on the determinants of social ties. Finally, we review evidence from a field experiment we conducted in the firm to highlight one particular mechanism through which social capital significantly affects worker performance.

This paper studies the formation of social capital in a firm - as embodied in the network of friendship ties between its workers. The idea that human relations affect performance in the workplace has been long recognized (Marshall, 1890, Mayo, 1933, Barnard, 1938, Roethlisberger and Dickson, 1939, Roy, 1952 and Bewley, 1999), and there is now a burgeoning theoretical literature incorporating such social concerns into the analysis of behavior within firms (Encinosa et al., 1997, Kandel and Lazear, 1992 and Rotemberg, 1994). Moreover, the increasing availability of personnel data has allowed progress to be made in identifying the qualitative importance that social ties between co-workers have on worker behavior (Ichino and Maggi, 2000, Bandiera et al., 2005 and Mas and Moretti, 2006).3 The existence of social ties between workers can be beneficial to the firm's overall performance if socially tied workers are, for example, more likely to cooperate and share information with each other (Lazear, 1989 and Ichniowski and Shaw, 2005), more likely to trust each other and so not engage in opportunistic behavior (Nagin et al., 2002 and Fehr and List, 2004), more likely to internalize any positive externalities their behavior has on their friends within the firm because of social pressures or mutual monitoring (Mas and Moretti, 2006), or because workers are compensated according to team pay (Jones and Kato, 1995, Knez and Simester, 2001, Hamilton et al., 2003 and Hayes et al., 2006). On the other hand, such social ties may be to the detriment of the firm if, for example, socially tied co-workers exert peer pressure on each other to enforce norms of low effort (Roy, 1952, Ichino and Maggi, 2000 and Bandiera et al., 2005), workers engage in collusive behavior against the principal (Tirole, 1986 and Kofman and Lawarree, 1993), workers engage in influence activities with managers they are socially tied to (Milgrom, 1988), or managers display favoritism towards workers they are socially connected to (Prendergast and Topel, 1996).4 In short, the existence of social ties between workers impacts on nearly all aspects of firm and worker behavior, including how workers can be expected to respond to a given set of incentives, the optimal compensations structures for workers at different tiers of the firm hierarchy, and the optimal organizational design of the firm. Taking account of social capital within the firm may therefore help explain differences in the behavior of workers in the same workplace, as well as differences in the structure and performance of otherwise observationally similar firms. In this paper, we first analyze the formation of social capital - as embodied in the network of friendship ties among co-workers - in a leading UK farm producer of soft fruit. We then review evidence from a field experiment we conducted on the farm to highlight one particular mechanism through which social capital significantly affects worker performance (Bandiera et al., 2006). By focusing on social ties within the firm, we build on the previous literature which has emphasized the role that social networks play in enabling individuals to find employment in the first place. In Granovetter's (1974) seminal study, he found the majority of surveyed residents of a Massachusetts town had obtained their jobs through social contacts, a finding confirmed by international comparative evidence (Pellizzari, 2004). There is also evidence of the importance of social networks on the demand side of labor markets such that firms use the social networks of their workers to fill vacancies (Fernandez and Weinberg, 1997). Calvo-Armengol and Jacson (2004) develop a model of social networks in labor markets that makes precise implications for social mobility, patterns of unemployment across demographic groups, and the incentives individuals have to participate in the labor force. We also note that another branch of the literature has shown the importance of the CEO or managerial board of firms being socially connected to those outside of the firm such as local politicians and bureaucrats (Mian and Khwaja, 2005). We use two sources of data for the analysis. The first is a survey we administered to workers to elicit information on their network of friends in the workplace. We first use this to describe the social ties that each worker has to their co-workers, as well as the network of social ties in the firm as a whole. We then present evidence on how friendships form in the workplace. The data allows us to make a distinction between the friendship ties that existed between workers prior to their arrival at the workplace, and those that form in the workplace itself.5 The final part of the paper briefly review evidence from a field experiment in the firm in which we exogenously changed managers' incentives from fixed wages to performance pay based on the average productivity of managed workers. The field experiment was designed to shed light on the interplay between social ties, managerial incentives, and workers' performance. The paper is organized into six sections. Section 2 describes our context and data. Section 3 describes the social ties of workers and the network of ties as a whole. Section 4 presents evidence on the formation of friendships. Section 5 reviews evidence on the interplay between social connections between workers and managers, and the compensation scheme of managers. Section 6 concludes with a discussion of the external validity of our findings.

This paper has presented evidence on the social capital in one particular firm, as embodied in the friendship ties among workers. We describe the structure of the friendship network as a whole and present evidence on the determinants of social ties. Having data from one firm naturally raises issues of the external validity of our results. The firm we study, as any other, has unique features that shape social connections between workers and managers and their effect on productivity. In particular, in this setting managers and workers are of similar ages and backgrounds, they are predominantly young individuals, and they live on the farm site for the entire duration of their stay. All these features increase the likelihood that they form strong social connections with one another. In other settings, social connections might be less likely to form or to be strong enough to affect behavior. On the other hand, the workers in this study are employed on short term seasonal contracts and so long run social ties are less likely to form relative to other firms. More generally, in other settings we would expect the existence of social ties between workers to impact on aspects of firm and worker behavior, including how workers respond to a given set of incentives, the optimal compensations structures for workers at different tiers of the firm hierarchy, and the optimal organizational design of the firm. Taking account of social capital within the firm may therefore help explain both differences in the behavior of workers in the same workplace environment, as well as differences in the structure and performance of otherwise observationally similar firms. Integrating social capital into models of the production function of the firm, may help better reconcile empirical observations with the predictions of economic theory. It has been previously noted in the literature that there is greater variation in compensation contracts than can be explained by standard models of contracting (Baker et al., 1988), and that factors such as job design, human resource policies, and participative decision making, all have significant effects on productivity (Ichniowski et al., 1997). A number of steps have been taken in this direction. For example, Ichniowski et al. (2003) develop a model that incorporates an organization's ‘connective capital’ - defined as the stock of human capital that employees can access through their connections to other workers - as an input into its production function. An important implication of this modelling framework is that by forming connections to each other, workers create positive externalities in the information available to other workers. As workers do not internalize these social returns when forming connections, this provides an underlying justification to why firms are observed investing resources into fostering links between workers, such as team building exercises. Similarly, Akerlof and Kranton (2005) discuss how expanding standard models to incorporate the concept of identity can help us to better understand incentives within firms, and the organization of firms. While these are the first steps, they highlight the challenges and rewards of a research agenda that brings together work from sociology, psychology, anthropology, and management, into eco-nomic theories of the firm.