An AI-powered writing assistant designed by Purdue developers provides timely feedback to strengthen student writing. (Purdue University photo)
Imagine a world where students could receive detailed, timely feedback on their writing before handing in their work for grading. What if that feedback was tailored to fit the specific rubric set by their instructor? Welcome to Charlie, an AI-driven writing assistant created by Purdue University’s instructional technology team and integrated within the Circuit peer-review platform.
“One of the major challenges with peer review has always been the reliability of the reviewers,” said Jason Dufair, the lead application developer. “Circuit offers a framework to calibrate students, who also act as reviewers in later stages of the assignment, against a set of pre-graded assignments provided by the instructor.”
Initially launched around 2015, Circuit was designed by Purdue developers to improve instructional technology and create a strong peer-review system. Over the years, it has transformed into a versatile tool that instructors can customize to meet their specific course requirements, including options for self-review and instructor feedback. The introduction of Charlie marks a pivotal advancement in this ongoing evolution, effectively meeting the increasing demand for actionable and prompt writing feedback.
Lindsay Hamm, an assistant teaching professor in sociology, has been instrumental in guiding the development of Charlie since 2019. Originally, Charlie provided basic point estimates for essays, but it has since progressed to offer in-depth, constructive comments tailored to each section of an assignment’s rubric. This enables students to identify areas that require improvement and make revisions prior to submission.
As Dufair emphasizes, a key point is that Charlie does not assign grades to students’ work. Instead, it serves as a resource to help identify opportunities for strengthening arguments and better fulfilling rubric criteria prior to grading.
In its early stages, Charlie could predict a student’s score but did little to help enhance their writing quality. Developers collaborated with the Purdue Online Writing Lab and instructors like Hamm to train Charlie to deliver more qualitative, actionable feedback. While Charlie offers general guidance, it refrains from suggesting specific word changes or actions, reducing student anxiety and resembling the type of constructive feedback available during office hours or in writing labs.
“It’s crucial to remember that no matter how strong the writing is, Charlie will always identify areas for improvement,” remarked Casey Wright, lead application developer. “We try to prepare students for that.”
The effectiveness of Charlie’s feedback heavily relies on the quality of the rubric for each assignment. Hamm collaborated with the instructional technology team to create built-in rubric templates, simplifying the adaptation of Charlie for various courses.
With Circuit’s integration into Brightspace and the recent feature allowing students to opt for Charlie’s feedback on submission-only assignments, the team has worked tirelessly to significantly lower barriers for course adoption, according to Wright.
What Sets Charlie Apart from Other AI Tools?
Much like a toolbox that contains various instruments for specific tasks, different AI tools serve different purposes. Some AI solutions generate novel hypotheses or provide general writing guidance, while Charlie’s feedback is closely aligned with the specific needs of a course or instructor.
Supported by the University Innovation Alliance, Purdue’s approach stands out for focusing on rubric-guided, constructive feedback rather than generic writing suggestions. Hamm points out that Charlie not only boosts students’ writing confidence but also enhances their abilities to give and receive peer feedback, enriching academic discussions and collaboration.
“Now a student can come in and say, ‘Charlie keeps saying my counterargument isn’t very strong’ or ‘Charlie says my thesis statement could be narrower.’ This allows me to focus on those higher-order issues that need addressing,” Hamm said. “My hope for AI — and I know it’s a hopeful vision — is that it will help break down barriers and foster more meaningful conversations as people have greater access to information.”
Charlie’s successful implementation in sociology has sparked interest from other departments, including pharmacy and graduate governance courses.
From a cybersecurity perspective, interacting with Charlie is as secure as any other data sharing within Purdue’s digital environment. Protecting privacy and data security is a top priority when managing student information, and all interactions are compliant with the Family Educational Rights and Privacy Act standards. Furthermore, engaging with Charlie is entirely optional.
Charlie represents Purdue’s commitment to utilizing technology for enhancing student success, offering a scalable, supportive, and effective tool for improving writing skills across campus.
Getting Started with Circuit’s Charlie
Faculty interested in using Circuit can log in at peercircuit.org, link their courses to Brightspace, and set up assignments with just a few clicks. Comprehensive help resources and direct support are accessible at tlt@purdue.edu. Additionally, instructors can access detailed demonstrations and resources from a fall 2025 session titled “Open Kitchen: Exploring AI Tools Together,” as part of the AI Bytes workshop series.
