Assessing Problem Decomposition In Cs1 For The Genai Era

Samvrit Srinath, University of California San Diego

Annapurna Vadaparty, University of California San Diego

David H. Smith IV, Virginia Tech

Leo Porter, University of California San Diego

Daniel Zingaro, University of Toronto

Date

11/2025

AI Overview

Why it matters

As generative AI lets introductory students easily generate code, problem decomposition becomes critical for specifying requirements. However, educators lack consensus on how to best teach and assess decomposition in introductory computing courses.

Study at a glance

Question: How can instructors effectively scaffold and assess problem decomposition skills in an introductory computer science course?
Setting and data: Introductory computing course at a large research university in North America, 10-week term, 181 enrolled students.
Method: Design-based research and descriptive analysis of course assignments, lab activities, and classroom observations.
AI tools: GitHub Copilot

Key findings

Lengthy problem descriptions initially caused students to guess and check multiple-choice answers, prompting the design of initial non-programming conceptual probes to ensure comprehension before architectural reasoning.
Multi-part question suites effectively scaffolded decomposition by guiding students through conceptual probes and component-level debugging, testing, or interface tasks before presenting final helper-function selection questions.
When asked to draw decomposition diagrams, many students succeeded, though some represented data flow or temporal sequencing rather than function-calling relationships alone.

Summary drafted with AI from the full paper and may contain errors. See the full paper for details.

Problem decomposition--the ability to break down a large task into smaller, well-defined components--is a critical skill for effectively designing and creating large programs, but it is often not included in introductory computer science curricula. With the rise of generative AI (GenAI), students even at the introductory level are able to generate large quantities of code, and it is becoming increasingly important to equip them with the ability to decompose problems. There is not yet a consensus among educators on how to best teach and assess the skill of decomposition, particularly in introductory computing. This practitioner paper details the development of questions to assess the skill of problem decomposition, and impressions about how these questions were received by students. A challenge unique to problem decomposition questions is their necessarily lengthy context, and we detail our approach to addressing this problem using Question Suites: scaffolded sequences of questions that help students understand a question's context before attempting to decompose it. We then describe the use of open-ended drawing of decomposition diagrams as another form of assessment. We outline the learning objectives used to design our questions and describe how we addressed challenges encountered in early iterations. We present our decomposition assessment materials and reflections on them for educators who wish to teach problem decomposition to beginner programmers.