With the phones in their pockets, millions of people have access to sensing, computation, and connectivity, making it possible to harness the power of the crowd to collect and share data about their surroundings and experiences on a massive scale. Crowdsensing/crowdsourcing is a novel data collection paradigm that leverages this vast mobile sensor network, making it possible to expand the scope of research endeavors and address civic issues without requiring the purchase of specialized sensors or the installation and maintenance of network infrastructure. Data collected using such applications may come from unexpected yet interesting and valuable sources and may allow for collecting data in previously inaccessible locations and contexts. This new data collection paradigm introduces several research challenges. Privacy is a primary concern for users that are contributing sensitive or identifying data. Incentive mechanisms for participation may be needed to encourage people to volunteer their resources to collect data. Methods are needed for processing large-scale, user-generated data sets into meaningful information, and for assessing and understanding the quality of information to help guide decision-making. Approaches that involve the crowd in such data analysis tasks, with humans serving as a source of semantic information, interpretation, and evaluation of crowdsensed/crowdsourced data, can also help to build an understanding of the physical, computational, and socio-technical environment. The CASPer workshop provides a forum for discussion, debate, and collaboration focused on ideas, trends, techniques, and recent advances in crowdsensing/crowdsourcing. We invite original research contributions that advance the state of the art as well as position papers that pose a new direction or present a controversial point of view. CASPer will be held in conjunction with IEEE PerCom 2015 (March 23-27) in St. Louis, Missouri, USA. Accepted papers will be published in the IEEE PerCom Workshop Proceedings.