This supplementary material contains the interview_script, the dashboard interface (community_growthUI.png, project_growthUI.png), the rising_contributor_recommendation_approach and maintainers_suggestions_table that were used for the paper Attracting and Retaining OSS Contributors with a Maintainer Dashboard (ICSE SEIS 2022). the interview_script.pdf is the script used to interview open-source project maintainers. The community_growthUI.png and project_growthUI.png showcase the dashboard interface as presented to open-source project maintainers. rising_contributor_recommendation_approach.pdf depicts the implementation approach we used to identify and recommend rising contributors in an open source project. maintainers_suggestions_table.pdf compiles the suggestions our interviewed maintainers had on improving the dashboard.