# The link graph, measured — 2026-07-27

The protocol committed to this before the essay could state a mechanism: *"'The link graph rewards
the free version' is currently the best explanation for eight of eight, and it is still an
explanation rather than a measurement."*

Now measured. Source: DataForSEO Backlinks, bulk page summary, live index, 2026-07-27.

---

## Q4 · Brynjolfsson, Li & Raymond

| Version | Referring domains | Backlinks | First seen |
| --- | --- | --- | --- |
| **Preprint** — `nber.org/papers/w31161` | **1,884** | 4,585 | 2023-05-01 |
| **Version of record** — `academic.oup.com/qje/article/140/2/889/7990658` | **631** | 1,218 | 2025-02-24 |

**Preprint advantage: 3.0× referring domains, 3.8× backlinks, a 21-month head start.**

## Q5 · Dell'Acqua et al.

| Version | Referring domains | Backlinks | First seen |
| --- | --- | --- | --- |
| **Preprint** — SSRN `4573321` | **1,058** | 2,141 | 2023-09-17 |
| **Preprint** — HBS landing page | **606** | 1,154 | 2023-09-28 |
| **Preprint** — HBS working-paper PDF | **511** | 1,337 | 2023-10-15 |
| **Version of record** — `pubsonline.informs.org/doi/10.1287/orsc.2025.21838` | **53** | 100 | 2026-03-14 |

**Preprint advantage: 20× referring domains against SSRN alone**, and the preprint exists on *three*
separately-linked surfaces, each of which individually outweighs the version of record by an order of
magnitude. The version of record is four months old.

---

## Why this settles the mechanism

The two questions differ in outcome, and the link data predicts the difference precisely.

| | Preprint : VoR referring domains | VoR age at run | Systems citing the VoR |
| --- | --- | --- | --- |
| **Q4** | 3 : 1 | 17 months | **1 of 4** (Claude, on both runs) |
| **Q5** | 20 : 1 | 4 months | **0 of 4**, and 0 of 9 runs |

Where the version of record has had time to accumulate a third as many referring domains as its
preprint, one retrieval stack finds it. Where it has a twentieth, none does.

**This is no longer "paywalled papers lose."** Both versions of record are paywalled; both preprints
are free. What separates them is **link mass and age**. The claim the essay can now make is narrow,
mechanistic and measured:

> A published paper has to out-age its own preprint in the link graph before retrieval will find it.
> Until it does — and that takes years — the numbers you get are the ones the authors already revised.

For Q5 that window is still open, four months after publication and three years after the preprint.
Every finding published this year is inside it.

## A detail that needs interpreting, not asserting

The *Organization Science* page reports **85 of its 100 backlinks as broken**, and `broken_pages: 1`.
On the other five URLs the field is absent. That is consistent with the publisher returning an error
or a block to crawlers, which would compound the link deficit — a version of record that is both
sparsely linked *and* hard to crawl. **It is also consistent with an artefact of one crawler's
access.** It is recorded here as observed and is not used to support any claim until it is checked
against a second source.

## Limits of this measurement

- **One commercial crawler's index, not the web.** DataForSEO's view is a proxy. It is not the index
  any of these four assistants retrieves from, and no vendor publishes theirs.
- **Referring domains are not retrieval rank.** The correlation across two questions is strong and
  directionally right; two points is not a model.
- **Single snapshot**, 2026-07-27. The whole point of the finding is that these numbers move.
- The comparison is **URL-level**. Both papers are reachable at other addresses — repositories,
  mirrors, author pages — that are not counted here. Counting more preprint surfaces would widen the
  gap, not narrow it, so the figures above are conservative in the direction of the argument, which
  is the safer direction to be wrong in.