Context: Hackathons have become popular events for teams to collaborate on projects and develop software prototypes. Most existing research focuses on activities during an event with limited attention to the evolution of the hackathon code. Objective: We aim to understand the evolution of code used in and created during hackathon events, with a particular focus on the code blobs, specifically, how frequently hackathon teams reuse pre-existing code, how much new code they develop, if that code gets reused afterwards, and what factors affect reuse. Method: We collected information about 22,183 hackathon projects from Devpost and obtained related code blobs, authors, project characteristics, original author, code creation time, language, and size information from World of Code. We tracked the reuse of code blobs by identifying all commits containing blobs created during hackathons and identifying all projects that contain those commits. We also conducted a series of surveys in order to gain a deeper understanding of hackathon code evolution that we sent out to hackathon participants whose code was reused, whose code was not reused, and developers who reused some hackathon code. Result: 9.14% of the code blobs in hackathon repositories and 8% of the lines of code (LOC) are created during hackathons and around a third of the hackathon code gets reused in other projects by both blob count and LOC. The number of associated technologies and the number of participants in hackathons increase reuse probability. Conclusion: The results of our study demonstrates hackathons are not always "one-off" events as the common knowledge dictates and it can serve as a starting point for further studies in this area.

Background: Hackathons have become popular events for teams to collaborate on projects and develop software prototypes. Most existing research focuses on activities during an event with limited attention to the evolution of the code brought to or created during a hackathon. Aim: We aim to understand the evolution of hackathon-related code, specifically, how much hackathon teams rely on pre-existing code or how much new code they develop during a hackathon. Moreover, we aim to understand if and where that code gets reused. Method: We collected information about 22,183 hackathon projects from Devpost- a hackathon database - and obtained related code (blobs), authors, and project characteristics from the World of Code. We investigated if code blobs in hackathon projects were created before, during, or after an event by identifying the original blob creation date and author, and also checked if the original author was a hackathon project member. We tracked code reuse by first identifying all commits containing blobs created during an event before determining all projects that contain those commits. Result: While only approximately 9.14% of the code blobs are created during hackathons, this amount is still significant considering time and member constraints of such events. Approximately a third of these code blobs get reused in other projects. Conclusion: Our study demonstrates to what extent pre-existing code is used and new code is created during a hackathon and how much of it is reused elsewhere afterwards. Our findings help to better understand code reuse as a phenomenon and the role of hackathons in this context and can serve as a starting point for further studies in this area.

Background: Hackathons have become popular events for teams to collaborate on projects and develop software prototypes. Most existing research focuses on activities during an event with limited attention to the evolution of the code brought to or created during a hackathon. Aim: We aim to understand the evolution of hackathon-related code, specifically, how much hackathon teams rely on pre-existing code or how much new code they develop during a hackathon. Moreover, we aim to understand if and where that code gets reused, and what factors affect reuse. Method: We collected information about 22,183 hackathon projects from Devpost- a hackathon database - and obtained related code (blobs), authors, and project characteristics from the World of Code. We investigated if code blobs in hackathon projects were created before, during, or after an event by identifying the original blob creation date and author, and also checked if the original author was a hackathon project member. We tracked code reuse by first identifying all commits containing blobs created during an event before determining all projects that contain those commits. Result: While only approximately 9.14% of the code blobs are created during hackathons, this amount is still significant considering time and member constraints of such events. Approximately a third of these code blobs get reused in other projects. The number of associated technologies and the number of participants in a project increase reuse probability. Conclusion: Our study demonstrates to what extent pre-existing code is used and new code is created during a hackathon and how much of it is reused elsewhere afterwards. Our findings help to better understand code reuse as a phenomenon and the role of hackathons in this context and can serve as a starting point for further studies in this area.