Can LLMs Really Understand Item Difficulty Levels? Implications for Automated Item Generation Using LLMs
Source
Xinyi Wang, Hong Jiao, Ming Li, Sydney Peters, Hanna Choi, Tianyi Zhou, Qingshu Xu
Author
Xinyi Wang, Hong Jiao, Ming Li, Sydney Peters, Hanna Choi, Tianyi Zhou, Qingshu Xu
Date
Key takeaways · AI-distilled
The scoreboard in quadratic weighted kappa (agreement with the true label, credited partially for near misses): best LLMA large language model — the neural network behind tools like Claude and ChatGPT, trained on huge amounts of text to predict what comes next.Full definition → 0.578, ConvBERT 0.625. A small encoder trained on the task beats a frontier model prompted for it.
Both learned models also beat the hand-engineered feature baseline, so the story isn't neural versus classical. It's task-specific training versus general-purpose prompting.
Why prompting fails here: projecting the item embeddingA list of numbers representing a piece of text's meaning, so that similar meanings end up numerically close and can be searched.Full definition → down to a low-dimensional map, easy and hard items sit on top of each other. Difficulty barely registers in the text's meaning, so a model reading meaning has little signal to read.
No prompting configuration rescued it. Across several models and strategies the winner was plain zero-shot at temperature 0, meaning the ceiling was the approach, not the prompt.
Terms in this piece · Glossary
LLM — A large language model — the neural network behind tools like Claude and ChatGPT, trained on huge amounts of text to predict what comes next.
calibration — How well a model's confidence matches reality — a calibrated model saying "90% sure" is right about 90% of the time.
benchmark — A standard public test set for comparing AI models — the shared scoreboards behind every "model X beats model Y" claim.
embedding — A list of numbers representing a piece of text's meaning, so that similar meanings end up numerically close and can be searched.
Why it matters
If you're using LLMs as judges or graders for difficulty/quality estimation tasks, this shows that scaling to more capable models (GPT-5 vs GPT-4.1) can actually degrade calibrationHow well a model's confidence matches reality — a calibrated model saying "90% sure" is right about 90% of the time.Full definition → on hard cases, and that a purpose-built encoder model still beats zero-shot LLM prompting on this benchmarkA standard public test set for comparing AI models — the shared scoreboards behind every "model X beats model Y" claim.Full definition →.
Key quotes
“Zero-shot GPT-4.1 with a temperature of 0 yielded the highest item difficulty level prediction accuracy, with a quadratic weighted kappa (QWK) of 0.578.”
“However, LLMs' prediction accuracy was lower than that of ConvBERT (QWK = 0.625), which outperformed the best feature-based supervised machine learning model.”
“Further analysis showed that all LLMs struggled to label hard items; in particular, the current advanced GPT-5.4 tended to underestimate item difficulty levels.”