Large Language Model (LLM)
Definition
A neural network trained on large text corpora to predict likely next tokens. At inference, it generates text by sampling from probability distributions over vocabulary, producing output that is statistically smooth and consistent with its training distribution.
- Core mechanism
- Next-token prediction over vocabulary probabilities
- Training input
- Large text corpora
- Output character
- Statistically smooth, consistent with training distribution
- Forensic relevance
- Authorship and AI-text detection in questioned documents
Common questions
Why is LLM-generated text hard to distinguish from human writing?+
Because the model is trained to produce text that closely matches the statistical patterns of large human-written corpora, so surface fluency and grammar offer little discriminating signal. Detection instead relies on subtler cues like perplexity, burstiness, or watermarking.
Can an examiner reliably prove a document was LLM-generated?+
Detection tools estimate probability rather than certainty, and their accuracy degrades with paraphrasing, editing, or short passages. Courts generally treat such findings as investigative leads rather than conclusive proof of authorship.
Related terms
- AI Detection Classifier
- A machine-learning system trained to discriminate between human-written and LLM-generated text by measuring features such as perplexity, burstiness, and n-gram probabilities. Current...
- Burstiness
- The variance in sentence-level complexity across a passage. Human writing tends to mix complex and simple sentences unevenly; LLM output tends to...
- Human-LLM Collaboration
- Text production in which a human contributes prompts, editing decisions, and intentional content while an LLM generates or transforms the prose. The...
- Perplexity
- A measure of how surprising a sequence of words is to a language model. LLMs tend to generate low-perplexity text (predictable word...
- Stylometric Signature
- The set of measurable linguistic features : function-word frequencies, sentence length, punctuation patterns, vocabulary richness : that characterises a specific writer's output...