‘Cheating under watch’: How India is using AI to detect exam fraud

An AI detector tool is software that analyzes text to estimate the probability that it was generated by an AI language model. These tools use statistical analysis of writing patterns — including perplexity, burstiness, and vocabulary distribution — to distinguish AI-generated text from human writing. They are widely used by educational institutions for academic integrity.

GPTZero, Originality.ai, and Turnitin AI are considered among the more reliable AI detection tools, though all have meaningful false positive and false negative rates. Reliability varies by text length (longer texts are scored more accurately), model used to generate text, and whether the text was post-processed. No tool is reliable enough to serve as sole evidence of AI authorship.

Free AI detector tools like GPTZero's free tier and ZeroGPT provide reasonable accuracy for clearly AI-generated text but have higher false positive rates than premium tools. For high-stakes academic integrity decisions, institutions typically use premium tools like Turnitin or Originality.ai that are validated against larger and more diverse text corpora.

Most AI detector tools report a probability of AI authorship rather than identifying which specific model produced the text. Some tools like Originality.ai attempt to flag likely GPT-4 versus GPT-3.5 writing, but reliable attribution to a specific AI model remains technically challenging and is not currently a reliable feature of any widely available tool.