Relationship between how bug reports are closed and developer retention. Research objective: To explore how the timing, or other features, related to how bug reports are closed, could influence core developer retention in a FOSS (free, open source software) project. Example of RQ: Does a longer time-to-close for bug reports cause developers to stop earlier contributing to the source code of a project? Method: Retrieve **data** about the issues (including bug reports) for a large and diverse set of FOSS projects, if possible with different issue tracking systems, so that specific features of it don't affect the results. Retrieve **data** from the source code management system of the same projects. Once all the **data** retrieved is stored in a database, use it to explore different proxies for time-to-close bug reports and for estimating periods of continuous contribution. For estimating time-to-close, explore different strategies for telling bug reports apart from other issues (machine learning on title and description, tags, etc). For estimating periods of contribution explore different approaches (maximum period without contributions, number of contributions over a certain period, etc.) to tell apart frequent (likely core) contributors from casual contributors. Then, explore how to estimate the period until stopping contributions (considering extending temporary periods, such as vacation). Once the most reliable method is exactly defined, conduct the study in as many repositories as possible. Personal trajectories in software development. Research objective: Explore ways to track trajectories of developers, by analyzing their footprints in different kinds of software development repositories. Example of RQ: Do core contributors usually follow a path from messages in communication channels to issue submitters, to code review submitters? Method: Retrieve **data** from mailing lists, GitHub issues and pull requests, and GitHub Git repositories, for a large collection of projects. Merge identities using email addresses for linking identities in email messages to identities in Git commits, and the GitHub commit API to link email addresses to GitHub user IDs. If possible, improve identities **data** by manually merging and de-merging identities using other **data** sources (for example, public Internet profiles). Once the identities **data** is curated, use it to identify contributions by persons in all **data** sources, and explore the different tracks followed.