Dr. Sarah Chen

General 8 min

Dr. Sarah Chen • 4 days ago

A Short History of AI-Generated Code Detection

A CS professor traces how AI-generated code detection grew out of MOSS-era token fingerprints, code stylometry, and a broken similarity assumption. The piece explains how modern detectors work, where they still stumble, and why stacked peer, web, and AI signals make the most defensible academic workflow.

Read

General 11 min

Dr. Sarah Chen • 1 week ago

Why a 400-Student Intro Course Adopted Layered Code Checks

One CS department's switch from a single similarity tool to a layered detection workflow changed what they could see in student code. Peer copying, web sources, and AI-generated submissions each required different signals, and combining them revealed more than any one check alone.

Read

General 10 min

Dr. Sarah Chen • 2 weeks ago

AI Code Detector Comparison Across Codequiry, GPTZero, and Copyleaks

A CS professor ran 1,200 Java submissions through three AI code detectors. Codequiry caught 94% of known AI files and flagged only 3.5% of pre-LLM human code, while the other tools posted two to three times that false positive rate. The full numbers and methods are below.

Read

General 11 min

Dr. Sarah Chen • 2 weeks ago

How a CS Professor Spots Refactored Code Plagiarism in Java Labs

This is the workflow Dr. Sarah Chen uses every week to catch plagiarism that survives renaming, reordering, and refactoring. It layers token normalization, AST comparison, and a smart review queue, then walks through what to look for in a diff before talking to a student.

Read

General 11 min

Dr. Sarah Chen • 1 month ago

What Happens When a CS Course Runs Both MOSS and ChatGPT Detectors

Over 1,200 student submissions from a large public university’s introductory Python course were analyzed with Codequiry’s similarity engine and its AI code detector. The results show how traditional plagiarism tools miss a growing fraction of unauthorized work—and why layering AI detection changes what instructors actually see.

Read

General 7 min

Dr. Sarah Chen • 1 month ago

Writing Programming Assignments That Resist Plagiarism

We cut similarity rates from 43% to 7% in a Data Structures course not by policing harder but by rewriting the assignments themselves. Here's what worked, what broke, and where detection tools like Codequiry still earn their keep.

Read

General 15 min

Dr. Sarah Chen • 1 month ago

How AST-Based Similarity Catches Disguised Code Plagiarism

Token-based plagiarism detectors match sequences of tokens, but smart students can evade them by renaming variables, reordering statements, and refactoring code. Abstract Syntax Tree (AST) comparison digs deeper into the structural DNA of a program, making it far harder to disguise copied code. Learn how AST-based detection works, why it catches what MOSS and JPlag miss, and where Codequiry’s multi-layered approach fits in.

Read

General 12 min

Dr. Sarah Chen • 1 month ago

Why CS Departments Are Now Running AI Checks After Plagiarism

When Midwestern State University’s CS department discovered that MOSS alone missed nearly a third of suspicious submissions—many generated by ChatGPT—they implemented a two-stage detection pipeline. This is what they learned about running plagiarism checks first, then AI detection, and why the combination caught more than either tool alone.

Read

General 11 min

Dr. Sarah Chen • 2 months ago

Designing Plagiarism-Resistant Programming Assignments

Copy-paste code and AI-generated solutions are flooding CS courses. Smart assignment design—parameterized prompts, incremental checkpoints, and open-ended specs—can make copying so cumbersome that students default to doing their own work. This deep dive builds a concrete, reusable playbook for instructors.

Read

General 8 min

Dr. Sarah Chen • 3 months ago

Why Some CS Departments Are Moving Beyond Moss for Plagiarism Detection

Riverdale State University’s computer science department spent years relying on Moss to catch plagiarised assignments. But as student work grew more sophisticated — combining copied web code, heavy refactoring, and AI-generated fragments — the department realised token-based similarity alone was no longer sufficient. This case study covers how they transitioned to a multi-tool detection pipeline.

Read

General 10 min

Dr. Sarah Chen • 4 months ago

Do AST-Based Engines Catch More Refactored Cheating Than Token-Based Ones

A mid-sized university CS department ran a controlled study comparing AST-based and token-based plagiarism detection across student assignments that had been systematically refactored. The results reveal which technique handles control flow restructuring, identifier renaming, and method reordering — and where both fail entirely.

Read

General 7 min

Dr. Sarah Chen • 4 months ago

The Open Source Audit That Nearly Bankrupted a Startup

When a promising fintech startup, Veritas Ledger, sought Series B funding, a standard due diligence audit spiraled into a crisis. Their core transaction engine, the product of a brilliant but rogue founding engineer, was built on stolen, copyleft-licensed code. The discovery didn't just delay the funding round; it put the company's very existence on the line. This is the story of how hidden code provenance almost destroyed a business.

Read