Why Large Language Models Fail at Tabular Prediction

AI gets wrecked by spreadsheets, and the comments are absolutely not being subtle

TLDR: The paper says chatbots mainly fail on table-based prediction because they break down when there are too many data columns, even as older methods still work well. Commenters instantly turned it into a fight over whether that proves a real weakness or just tests the AI in a silly, unrealistic way.

A fresh research paper set out to answer a surprisingly simple question: why are today’s superstar chatbots so bad at reading tables and making predictions from them? The authors tested a top-tier language model by feeding it full training and test data in one shot, then checked a bunch of possible excuses. Bad with messy data? Not the main issue. Confused by CSV files? Nope. Numbers tokenized weirdly? Also no. The real villain, according to the paper, is too many columns. As the data gets more complex, the model’s skill just falls apart, while old-school methods keep chugging along like smug office veterans.

And oh, the comment section smelled blood. One camp basically said, "This is not how anyone sane would use an LLM", with readers mocking the setup as “rawdogging” a chatbot without tools, helpers, or a proper workflow. Another camp was less interested in dunking on the paper and more interested in defending reality: maybe chatbots don’t “fail” here so much as classic table-crunching methods are just absurdly good. Then came the academic side-eye, with one commenter practically shouting, how do you publish this without even clearly stating the reasoning budget?

Naturally, the jokes landed too. The funniest drive-by suggested solving tabular prediction by having two AIs argue about tabs versus spaces—which, honestly, might be the most relatable coding joke in the whole thread. The big mood: the paper is intriguing, but the crowd is split between “important clue” and “lab experiment nobody would use in real life.”

Key Points

  • The paper investigates why generic large language models perform poorly on tabular prediction tasks despite success in many other domains.
  • The researchers test five hypotheses for LLM failure in a single-pass inference setting with no tools, scaffolding, or fine-tuning.
  • Controlled experiments reported in the article falsify four explanations: noisy or non-linearly separable data, CSV linearization, numeric tokenization, and the number of test points per query.
  • Input dimensionality is identified as the decisive factor, with LLM accuracy declining as dimensionality increases across 31 benchmark datasets.
  • In two dimensions, the LLM behaves similarly to a local distance-based method, but in higher dimensions no classical model reproduces its predictions.

Hottest takes

"Just have 2 LLMs debate whether tabs or spaces are the superior choice" — cyanregiment
"Rawdogging LLM isn't the tool for forecasting like this" — _joel
"utterly irrelevant to real-world use cases" — heaney-555
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