Human computation is a computing approach that draws upon human cognitive abilities to solve computational tasks for which there are so far no satisfactory fully automated solutions even when using the most advanced computing technologies available. Human computation for citizen science projects consists in designing systems that allow large crowds of volunteers to contribute to scientific research by executing human computation tasks. Examples of successful projects are Galaxy Zoo and FoldIt. A key feature of this kind of project is its capacity to engage volunteers. An important requirement for the proposal and evaluation of new engagement strategies is having a clear understanding of the typical engagement of the volunteers; however, even though several projects of this kind have already been completed, little is known about this issue. In this paper, we investigate the engagement pattern of the volunteers in their interactions in human computation for citizen science projects, how they differ among themselves in terms of engagement, and how those volunteer engagement features should be taken into account for establishing the engagement encouragement strategies that should be brought into play in a given project. To this end, we define four quantitative engagement metrics to measure different aspects of volunteer engagement, and use data mining algorithms to identify the different volunteer profiles in terms of the engagement metrics. Our study is based on data collected from two projects: Galaxy Zoo and The Milky Way Project. The results show that the volunteers in such projects can be grouped into five distinct engagement profiles that we label as follows: hardworking, spasmodic, persistent, lasting, and moderate. The analysis of these profiles provides a deeper understanding of the nature of volunteers' engagement in human computation for citizen science projects.
 Abstract Objectives Engagement at work has emerged as a potentially important employee performance and organizational management topic, however, the definition and measurement of engagement at work, and more specifically, nurse engagement, is poorly understood. The objective of this paper is to examine the current state of knowledge about engagement at work through a review of the literature. This review highlights the four lines of engagement research and focuses on the determinants and consequences of engagement at work. Methodological issues, as identified in the current research, and recommendations for future nurse-based engagement research are provided. Design A systematic review of the business, organizational psychology, and health sciences and health administration literature about engagement at work (1990–2007) was performed. Data sources The electronic databases for Health Sciences and Health Administration (CINAHL, MEDLINE), Business (ABI INFORM), and Psychology (PsycINFO) were systematically searched. Review methods Due to the limited amount of research that has examined engagement among the nursing workforce, published research that included varying employee types were included in this review. The selection criteria for this review include those studies that were: (1) written in English and (2) examined engagement at work in employee populations of any type within any work setting. Results The literature review identified four distinct lines of research that has focused on engagement within the employee work role. Of the 32 engagement-based articles referenced in this paper, a sample of 20 studies report on the examination of antecedents and or consequences of engagement at work among varying employee types and work settings. Key findings suggest organizational factors versus individual contributors significantly impact engagement at work. A common implication in this body of research was that of the performance-based impact. Conclusions The study of nurses' work engagement and its relationship to nurses' organizational behavior, including work performance and healthcare organizational outcomes can be achieved by first building upon a conceptually consistent definition and measurement of work engagement. Future research is needed to provide nurse leaders with a better understanding of how nurse work engagement impacts organizational outcomes, including quality of care indicators. We study how the visual catchiness (saliency) of relevant information impacts user engagement metrics such as focused attention and emotion (affect). Participants completed tasks in one of two conditions, where the task-relevant information either appeared salient or non-salient. Our analysis provides insights into relationships between saliency, focused attention, and affect. Participants reported more distraction in the non-salient condition, and non-salient information was slower to find than salient. Lack-of-saliency led to a negative impact on affect, while saliency maintained positive affect, suggesting its helpfulness. Participants reported that it was easier to focus in the salient condition, although there was no significant improvement in the focused attention scale rating. Finally, this study suggests user interest in the topic is a good predictor of focused attention, which in turn is a good predictor of positive affect. These results suggest that enhancing saliency of user-interested topics seems a good strategy for boosting user engagement.  Purpose - This paper aims to provide an overview of the recently introduced concept of work engagement. Design methodology approach - Qualitative and quantitative studies on work engagement are reviewed to uncover the manifestation of engagement, and reveal its antecedents and consequences. Findings - Work engagement can be defined as a state including vigor, dedication, and absorption. Job and personal resources are the main predictors of engagement; these resources gain their salience in the context of high job demands. Engaged workers are more creative, more productive, and more willing to go the extra mile. Originality value - The findings of previous studies are integrated in an overall model that can be used to develop work engagement and advance career development in today's workplace. Our research goal is to provide a better understanding of how users engage with online services, and how to measure this engagement. We should not speak of one main approach to measure user engagement --- e.g. through one fixed set of metrics --- because engagement depends on the online services at hand. Instead, we should be talking of models of user engagement. As a first step, we analysed a number of online services, and show that it is possible to derive effectively simple models of user engagement, for example, accounting for user types and temporal aspects. This paper provides initial insights into engagement patterns, allowing for a better understanding of the important characteristics of how users repeatedly interact with a service or group of services. The purpose of this article is to critically deconstruct the term engagement as it applies to peoples' experiences with technology. Through an extensive, critical multidisciplinary literature review and exploratory study of users of Web searching, online shopping, Webcasting, and gaming applications, we conceptually and operationally defined engagement. Building on past research, we conducted semistructured interviews with the users of four applications to explore their perception of being engaged with the technology. Results indicate that engagement is a process comprised of four distinct stages: point of engagement, period of sustained engagement, disengagement, and reengagement. Furthermore, the process is characterized by attributes of engagement that pertain to the user, the system, and user-system interaction. We also found evidence of the factors that contribute to nonengagement. Emerging from this research is a definition of engagement—a term not defined consistently in past work—as a quality of user experience characterized by attributes of challenge, positive affect, endurability, aesthetic and sensory appeal, attention, feedback, variety-novelty, interactivity, and perceived user control. This exploratory work provides the foundation for future work to test the conceptual model in various application areas, and to develop methods to measure engaging user experiences. © 2008 Wiley Periodicals, Inc.