Using GitHub Classroom To Teach Statistics

Figures & data

Table 1 Definitions of terms associated with Git and GitHub. Many definitions are modified from Bryan (2018) and GitHub Help (n.d.)

Term	Definition
Repository	Similar to a folder on Dropbox, except hosted on GitHub. Repositories sync with Git so that users can view a human-readable format of a project’s version control history on GitHub. In GitHub Classroom, each student assignment is a repository.
Commit	Rather than saving a file with a new name after file revisions, users can commit their revised work with Git. Each commit is associated with a commit message and a unique ID, allowing users to revisit changes made throughout the project. An example usage would be students committing changed code after writing a new function.
Push	After a user makes changes to files within a GitHub repository on their local computer, they can push these changes back to GitHub, so the changes can be seen by other users with access to the repository. This is similar to updating a file on a local computer and syncing the changes to Dropbox. An example usage would be students pushing a completed assignment to GitHub.
Pull	If a user wants to obtain the most up-to-date version of a GitHub repository, they can pull the changes to their local computer. This is similar to syncing changed files from a Dropbox folder to a local computer. An example usage would be an instructor pulling updated student assignment repositories.
Pull request	If a student makes changes to a shared repository, such as lecture notes, they can submit a pull request for the instructor to review these changes and to choose whether or not to integrate these changes into the shared repository.
Branch	If a student clones the course materials to their local computer, they can create their own branch. Changes made on this branch will not be reflected in the main version of the course materials, but can be merged using a pull request.
Issue	An issue is a suggested improvement to a GitHub repository, made through GitHub. For each issue, users can discuss the suggested changes in a forum. An example usage would be students submitting an issue for a mistake in an instructor’s lecture notes, within the lectures repository.
Clone	Users can clone a full GitHub repository onto their local computer, so they can edit code locally. Similar to downloading a folder from Dropbox, cloned repositories are synced to GitHub repositories, allowing for users to easily push and pull changes. An example usage is students cloning the repository which contains lecture notes.

Fig. 1 Creation and distribution of assignments with GitHub Classroom versus a University CMS. In both settings, the instructor begins with the homework assignment, which contains (starter) code, data, and instructions, on their local computer. With GitHub Classroom, the instructor pushes all parts of the assignment to the GitHub master organization. Using the GitHub Classroom interface, the instructor can create a homework repository for each student with a click of a button. Students then use git clone to download the homework assignment onto their local computers, maintaining the same directory structure and file names. Instructors using a CMS would have to upload each piece of the assignment individually. Each piece of the assignment is then downloaded individually by students. Because the students do not clone the whole assignment directory into their local computers, students can end up with different directory structures and/or different file names, which can result in difficulty running starter code and producing reproducible analyses.

Fig. 2 Grading assignments with GitHub Classroom vs. a University CMS. With GitHub Classroom (left side), students all finish the assignment with the same directory structure (bottom left). Students use the git push command to upload each piece of their assignment to the GitHub Classroom organization. The instructor then uses our shell script to download all assignments to their local computer, with one command. Because each assignment retains the same directory structure, the instructor can run student code which relies on reading in pieces of data. The instructor then pushes graded assignments with one command back to the GitHub Classroom organization. Using a university CMS, students first have to individually upload each part of the assignment that will be used for grading. Instructors then download each of the uploaded files, and lose all directory structures from students’ assignments. After (potentially) running student code and grading, instructors then have to individually upload each graded file back to the CMS.

Fig. 3 Using a master GitHub Classroom organization improves management of course material. An instructor who wishes to make a change to an assignment would make a change to the assignment in the master organization (red, bold, and italicized font denotes a changed file), which will then be present when creating new assignments. In this example, the instructor changed the dataset for the 2020 course iteration. In 2021, the new instructor added an additional analysis, which resulted in changing the assignment instructions and starter code.

Fig. 4 The number of repositories in the classroom organization becomes overwhelming. By the end of the semester, we had 256 repositories in the ICS course. This figure shows an example of what the organization page looks like at the end of the semester, when visited on GitHub. Student usernames are redacted for privacy.

Fig. 5 Students see instructor feedback in GitHub. After an instructor has provided feedback in a student’s assignment, the instructor then commits the feedback and pushes the updated file to the student’s assignment repository. By clicking on the commit message, the student then sees the feedback given by instructors, which is highlighted in green.

Bryan, J. (2018), “Excuse Me, Do You Have a Moment to Talk About Version Control?” The American Statistician, 72, 20–27. DOI: 10.1080/00031305.2017.1399928.

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