Scope & Significance Fit (pnas-fit)

Why this is skill #1

PNAS is selective, but its gate is different from Science/Nature. The bar is high-quality, broadly significant science — not only the single flashiest discovery of the year. A rigorous, important, well-supported paper that a general scientific audience would value has a real home at PNAS even if it is not top-1% headline news. Run this before investing in prose, and use it to make the realistic step-down call from Science/Nature.

When to trigger

• Before drafting, to decide if PNAS is the right venue.
• After a Science/Nature desk reject or transfer, to judge whether PNAS is the right next stop.
• When choosing among Science/Nature, PNAS, and a top field journal.
• When a co-author who is an NAS member offers to communicate the paper (then also run pnas-track).

PNAS's bar vs Science/Nature

PNAS values solid important science over only-the-flashiest. Do not under-sell a strong paper as "not good enough for PNAS" just because it would not lead Science; equally, do not inflate an incremental result.

The general-significance test

Imagine a reader from a different PNAS division (a cell biologist reading a physics paper, an economist reading a genetics paper). The paper passes if that reader would say "I understand why this matters and I'd want to know about it." PNAS spans Biological, Physical, and Social Sciences, so the cross-division reader is real — write for them.

Significance ladder (weak → strong)

1. Confirms an expected result in one system. (Weak — field journal.)
2. Extends a known effect to a new system/scale with clear added value. (Borderline — PNAS if the lesson is general.)
3. Resolves a question the broad community cares about. (Strong — solid PNAS.)
4. Reveals a previously unknown phenomenon, mechanism, or capability. (Strong — PNAS or up.)
5. Overturns a widely held assumption with decisive evidence. (Strongest — consider Science/Nature too.)

Rungs 2–4 are the PNAS sweet spot. Rung 5 may justify trying Science/Nature first; rung 1 points to a field journal.

Venue routing

Fatal weak-fit triggers

• The advance is incremental over the authors' own prior paper with no general lesson.
• The claim is narrow ("in our system, under our conditions…") and stays there.
• The "broad implication" is asserted, not demonstrated.
• Over-claiming: the conclusion outruns the evidence.

Output format

【Significance rung】 1–5 + one-line justification
【Cross-division reader test】 pass / borderline / fail (which other-division reader cares, and why)
【PNAS division (likely)】 Biological / Physical / Social Sciences
【Fatal triggers present】 [...]
【Recommended venue】 Science-Nature / PNAS / field journal / NEJM-Lancet
【If PNAS, the single sentence of broad significance】 "..."
【Next】 pnas-track (if PNAS) | reconsider venue (if fail)

Anti-patterns

• Do not rationalize a specialist result into "broad significance" with adjectives.
• Do not confuse technical difficulty with significance — hard ≠ important.
• Do not treat PNAS as merely "the journal you settle for" — it has a real, defensible bar.
• Do not let sunk cost drive the venue decision.