AI Grimoire
Note
8 min · revised 2d ago

How I read a paper in this field

Most of what I read does not replicate at my scale, on my data, with my budget. This is the filter I use to work out which parts might.

Open

This note is still open — I have not finished thinking it through. What is written below is where the reasoning has got to, including the parts I am not sure about, which are marked as such.

This is the least finished thing here and I am publishing it anyway, because writing it down has been more useful to me than getting it right would be.

The problem: far more is published than anyone can read, most results are reported at a scale I do not have, and the abstract is written to make the method sound general. I needed a filter.

The four questions

I ask these before reading past the method section, and they decide how much attention the rest gets.

1. What was held fixed, and is it neutral?

The Kaplan failure is the canonical example: a learning-rate schedule held constant across a sweep, penalising exactly the runs that varied the quantity being measured. The conclusion was wrong and nothing in the paper was sloppy.

So: what is constant across the comparison, and could it plausibly interact with the axis being varied? If the answer is “a hyperparameter tuned for one arm”, the result is about that tuning.

2. Is the baseline tuned as hard as the method?

Almost never. The authors spent months on their method and ran the baseline from a config file. A new optimiser beating AdamW at the authors’ AdamW settings is a much weaker claim than it appears, and papers rarely state how much search each arm received.

The tell is an ablation table where every row of the proposed method is tuned and the baseline is one row.

3. Does the improvement exceed the seed variance?

Bouthillier et al.’s number has stayed with me: on standard benchmarks, seed and data-order variation alone produces spreads comparable to the differences papers routinely report as improvements. A single-run comparison with a 0.4-point gap is not evidence of anything.

Three seeds with an interval is the minimum I now believe. Most papers report one, and the omission is usually not mentioned.

4. At what scale, and does the mechanism predict transfer?

This is the question I get most wrong. A result at 100M may or may not hold at 70B, and the way to guess is not the size of the gap but whether the mechanism depends on scale.

ScaleNorm is the cautionary case: a single scalar gain in place of a per-channel one, correct at the width it was tested at, wrong at the widths that came after — because the per-channel gain absorbs differences that grow with width. The mechanism had a scale dependence and the paper had no reason to notice.

What I do with the answers

Roughly three buckets.

Might be true for me. Mechanism is scale-free, baseline looks fairly treated, variance addressed. I will consider trying it, and I will run the baseline myself first.

True at their scale, unknown at mine. Most things. I note it and wait for someone else to report a replication at a size closer to mine.

Probably an artefact. Untuned baseline, single seed, a metric chosen after the fact. I read the related-work section for the citations and stop.

The parts I skip and the parts I read twice

Skipped: the introduction, the related work on first pass, and most of the results section.

Read twice: the experimental setup, in full, including the appendix — this is where question 1 is answered, usually inadvertently. And the limitations section where there is an honest one, which is rarer than it should be and a strong positive signal when present.

The best papers state their own confound. Porian et al. reconciling Kaplan and Chinchilla, Besiroglu et al. failing to reproduce a fit from the paper’s own figures, Schaeffer et al. manufacturing emergence to show it can be manufactured — these are the papers I trust most, and they share the property of trying to break their own result.

Still open

Things I have not worked out, which is why this note is marked unfinished:

How to weigh a result I cannot replicate at all. Frontier-scale findings — training dynamics at 400B, cluster-level behaviour — are unavailable to almost everyone and are also the ones that matter most for understanding what is happening. I have no procedure here beyond noting who reported it.

When to trust a benchmark number. Between contamination, judge bias and metric choice, I have gradually stopped believing most reported evaluations, and I do not have a replacement — only a vaguer sense of which sources have been careful before.

How much to discount for incentive. A paper from a lab shipping a product with the technique in it is not thereby wrong. But it is not independent evidence either, and I do not know what the correct adjustment is.

If I work any of these out I will revise this rather than write a second one.

Reference

The settled statements of what this note works through.

References

[1]Choshen et al. — A Hitchhiker’s Guide to Scaling Law Estimation (2024)arXiv:2410.11840
[2]Besiroglu et al. — Chinchilla Scaling: A Replication Attempt (2024)arXiv:2404.10102
[3]Bouthillier et al. — Accounting for Variance in Machine Learning Benchmarks (2021)arXiv:2103.03098

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