Since the rise of Open Innovation (OI hereafter) paradigm (Chesbrough, 2003), many scholars have investigated its effects on company performance or strategies (e.g. Lichtenthaler, 2009; Parida et al., 2012; Hung and Chou, 2013; Yun et al., 2018). The landscape for entrepreneurial initiatives has changed over the last years, and a growing number of Open Innovation Platforms (OIPs hereafter) entered the global arena as significant tools to help companies in leveraging new knowledge from the people (West and Bogers, 2014; De Falco et al., 2017). In recent years, several scholars have approached OIPs in order to explore their dynamics, and most of them focused on knowledge-based practices, platforms services and motivations of collaboration between participants (Frey et al., 2011; Kathan et al., 2014; Battistella and Nonino, 2012, 2013; De Falco et al., 2017; Randhawa et al., 2017; De Silva et al., 2018; Matricano et al., 2019). OIPs are a typical example of "two-sided platforms" as they connect two groups of users and operate as intermediaries (Belleflamme and Peitz, 2018). Two types of users populate the virtual OIPs on the demand side and the supply side (Troise et al., 2020): innovation seekers (the proponents of initiatives who launch online challenges) and backers (the innovators or problem solvers who support the initiatives and contribute to solve a challenge by sending their ideas). Despite the spread of OIPs and the growing interest by scholars and practitioners, only few studies have explored the successful drivers that lead initiatives to get superior performance through the online challenge (Troise et al., 2020). In this specific emerging research stream, little is known about the role of social capital in the success of these initiatives within OIPs. The aim of this study is to fill this gap by investigating the role of social capital in the success of online challenges within OIPs. Since social capital is a multidimensional concept, we consider the effects of its three main dimensions: cognitive, relational and structural ( Nahapiet and Ghoshal, 1998; Liu et al., 2010; Zheng et al., 2014). In line with the prior study of Zheng et al. (2014) who analyzed these three dimensions in the context of reward-crowdfunding platforms, we consider: shared meaning (i.e. the length of the description of initiatives posted on the OIP) as an expression of the cognitive dimension; obligation (i.e. the number of others' initiatives who the proponents of the challenge supported before the launch of their own initiative) as an expression of the relational dimension; social network ties (i.e. the number of proponents' friends on their main social networks, e.g. Facebook and LinkedIn) as an expression of the structural dimension. Based on the above, we propose the following theoretical framework (Figure 1) in order to explore the effects of social capital on the performance of online initiatives launched on OIPs. Figure 1. Theoretical Framework [GRAPHICS] We propose that social capital - i.e. cognitive dimension (H1), relational dimension (H2) and structural dimension (H3) - positively influences the performance of the initiatives launched on OIPs. Following the prior study of Troise et al. (2020), we consider two main parameters as proxies of initiatives' success: the number of ideas submitted at the end of the online call and the number of final backers involved. This research is a work in progress. We are collecting data from four main well-known OIPs (since their origin up to 2019): Opeindeo, Openinnovation-suedtirol, Guerra-creativa and Crowdspring. At the end of the data-collection we will have about 600 initiatives as final sample. In order to test the impact of social capital on initiatives' performance we will run two regression models (negative binomial or zero-inflated negative binomial regression as the two dependent variables are count parameters) in order to capture its effects on the final number of ideas (Model 1) and the number of backers (Model 2). We expect a positive impact of the three factors on both the initiatives' outcomes. The results of this research will add new knowledge in a nascent research stream and - hopefully will have both theoretical and practical implications for several stakeholders, in particular innovation seekers (especially companies and entrepreneurs), backers, platform managers and policy makers.
