Abstract
The purpose of this article is to identify the most impactful research on customer churn and to map the conceptual and intellectual structure of its field of study. Data were collected from the WoS database, comprising 338 articles published between 1995 and 2020. Several bibliometric techniques were applied, including analysis of co-words, co-citation, bibliographic coupling, and co-authorship networks. R software and the Bibliometrix/Biblioshiny package were used to perform the analyses. The results identify the most active and influential authors, articles, and journals on the topic. More specifically, through co-citations and bibliographic coupling, it was possible to map the oldest articles (retrospective analysis) and the current research front (prospective analysis). The retrospective analysis, based on co-citations, revealed that the foundations of this research field are constructs such as quality of service, satisfaction, loyalty, and changing behaviors. The prospective analysis, performed through bibliographic coupling, revealed that current research is embedded in predictive analysis, clusters, data mining, and algorithms. The results provide robust guidance for further investigation in this field.

Abstract
There is an increasing number of academic publications on studying the impact of the gig economy and digital platforms. Some of them involve entrepreneurship and business models. However, there is a lack of a global picture depicting the scientific structure of knowledge regarding the gig economy and entrepreneurship. This paper presents a conceptual, intellectual, and social bibliometric overview, using Bibliometrix and Biblioshiny (R-packages). To this end, total of 345 published articles were analyzed, covering 245 sources, 44 countries and 751 authors. There are several important findings: five main clusters emerged from the study (Self-employment and social economy; Sharing economy and sustainable development; Entrepreneurship and innovation; Gig economy and platform economy; and Digitalization); the main themes that emerge deal with sharing, gig, and platform economy, digitalization, teleworking, career participation and platforms; finally, gig workers are key for developing strategies, policies, and actions to achieve a social welfare through entrepreneurship in the platform ecosystem. It is also important to highlight the role of communities and social capital in the development of sustainable collaborative initiatives through digital entrepreneurship.

Abstract
The objective of this article is to analyze and empirically validate the differential effects in the daily schedules of the induced electricity prices by selling bids for three different technologies, namely hydraulic, thermal and renewable energy sources (RES), in hourly values, by daily observations for the year 2018. To achieve this objective, we employ an autoregressive distributed lag (ARDL) model-bound testing approach The results of the ADRL-ECM method, which also reports the long-run analysis, show that (a) the renewable and thermal technologies positively and significantly affect the electricity price for Endesa and Hidroeletrica del Cantabrico generators and (b) the hydraulic technology impacts negatively the electricity price, both at a 1% level of significance. In addition, following a long-term perspective it must be highlighted that RES negatively impact the price of electricity with a 1% level of significance for the Iberdrola, E.ON Energy, Union Fenosa and EDP Energy of Portugal generators. However based on a short-term perspective, the results report a positive effect between the quantities traded by hydraulic and thermal technologies on the electricity price for Endesa, Iberdrola, Hidroeletrica del Cantabrico and EDP Energy of Portugal, at a 1% level of significance. (C) 2022 The Author(s). Published by Elsevier Ltd.

Abstract
There has been a growing interest in academia regarding the term 'social innovation', including in disciplines such as sociology, administration, history, management, psychology, and economics. The literature highlights the lack of scientific clarity in the use of the term, and some scholars argue that the term is no more than a 'buzzword' or a 'fad'. This article focusses on the analysis of the conceptualizations of social innovation, contrasting sociological and economical approaches, and adopts an integrative approach to propose a categorization scheme of social innovation projects based on three distinct variables, namely the level of policy support, the profit orientation and the geographical scale. We argue that government support and the scalability of social innovations should be carefully pondered depending on the characteristics of the social innovation initiatives. We conclude that policy support should privilege social innovation initiatives that, while having the potential to deliver social good, are constrained by market failures. In addition, we also argue in favour of policy support for small bottom-up initiatives that have a profit-logic but are not sufficiently robust to survive on their own due to the liabilities of smallness and newness. Finally, we advise caution in public policies supporting scale-up strategies and highlighted the inherent challenges.

Abstract
This article aims is to address whether, and to what extent, socioeconomic conditions influence entrepreneurship-based activities in 18 European countries grouped into subregions (North, South, East and West) during the period 2008-2018. We conducted the empirical study under a two-stage DEA model. The results of scores of technical efficiency of the first stage of DEA show inefficiency in Northern Europe for Finland, Ireland and Sweden, while, Belgium, Germany, France and Luxembourg are also inefficient countries in Western Europe. Finally, Spain and Italy are inefficient in Southern European group of countries. In the second stage of DEA, through the parametric fractional regression model (FRM), which consolidated results of one-part and two-part models, the results show that the Expenditure on Social Protection produces positive (high magnitude coefficient) statistical significance on TEA of Eastern, Western and Southern EU countries, while generates a negative (high magnitude coefficient) statistical significance on TEA of Northern EU countries. Moreover, in the Eastern, Western and Southern EU countries, in contrast with Northern EU countries, presumably the dimensions of the social welfare (employment/unemployment protection and so on) are used to encourage individuals to invest in specific skills and/or new businesses. Furthermore, the results in this second stage of DEA helps gain a thorough perspective on how economic and social impacts result from TEA efficiency.

Abstract
The paper examines the relationship between gamification – the use of game elements in non-gaming contexts – and innovation teams’ outcomes. It builds on psychological and teamwork theories, arguing that gamification overcomes collaboration issues and generates multiple positive outcomes, particularly in coordination, alignment, engagement, and teams’ motivation. The research follows a qualitative theory-driven using a case study of an innovation project. The conceptual model built through the findings offers valuable insights about applying gamification in innovation teams, namely: i) surprising teams with such a new and playful approach reduces stress among team members; ii) rules and time constraints play a crucial role in teams’ coordination by avoiding dispersion and enhancing focused efforts. The paper provides a set of testable theoretical propositions derived from the conceptualization of gamification in the context of innovation teams. It supports innovation managers interested in measuring gamification outcomes in teams. © 2022 China Ordnance Society