---
title: "Bloom, Jones, Van Reenen & Webb (2020) found research productivity is falling sharply — reproducing Moore's Law now takes more than 18× the researchers of the early 1970s"
type: "claim"
status: "seedling"
audit_status: "capture-verified (the 2026-07-11 hop session read the primary PDF at web.stanford.edu/~chadj/IdeaPF.pdf via extract_pdf, tls:verified; an independent headless re-check of the verbatim phrasing was not run — no web-fetch tool is available in this promotion pipeline)"
source_url: "https://web.stanford.edu/~chadj/IdeaPF.pdf"
source_author: "Nicholas Bloom, Charles I. Jones, John Van Reenen, Michael Webb"
source_date: "2020-04-01T00:00:00.000Z"
source_quote: "the number of researchers required today to achieve the famous doubling of computer chip density is more than 18 times larger than the number required in the early 1970s"
source_tier: 1
provenance: "Promotion from 10-inbox/raw/2026-07-11-hop-population-scale-diminishing-returns.md, 2026-07-12 (headless)"
origin: "batch"
writer_model: "claude-opus-4-8"
derived_from: "10-inbox/raw/2026-07-11-hop-population-scale-diminishing-returns.md (id 20260711-1351-hop-population-scale-diminishing-returns)"
date_created: "2026-07-12T00:00:00.000Z"
tags: ["endogenous-growth","ideas-production","research-productivity","diminishing-returns","moores-law","economics"]
---


"Are Ideas Getting Harder to Find?" (Nicholas Bloom, Charles I. Jones, John Van
Reenen & Michael Webb, *American Economic Review* 110:4, 2020) decomposes economic
growth into **research productivity** (ideas produced per researcher) times the
**number of researchers**, and reports that across every case they examine — from
aggregate US growth to firm-level data to specific technologies — research
productivity is "declining sharply." Exponential progress is being sustained only
by throwing exponentially more inputs at it.

The paper's most-quoted instance is Moore's Law: "the number of researchers
required today to achieve the famous doubling of computer chip density is more
than 18 times larger than the number required in the early 1970s." Idea output per
researcher in semiconductors has fallen by a factor of roughly 18 in that window;
constant progress required a corresponding rise in the research workforce.

This is the **brake** on the engine described in
[[claim-kremer-1993-technology-growth-proportional-to-population]]: Kremer's
"more people → more ideas" runs forward into diminishing returns, where more minds
buy proportionally fewer breakthroughs. Critically, the poster child for the
decline — Moore's Law — is the very substrate on which the AI cost collapse of
[[claim-inference-cost-collapsed-280x]] rests, which is why that 280× figure is the
*weakest* instance of the scale-drives-improvement bridge: it lives in the exact
domain where economics documents the idea-engine sputtering. The same
sub-linear-returns law appears in biology
([[claim-desai-fisher-murray-2007-clonal-interference-logarithmic-speed-of-evolution]])
and, qualitatively, in neural scaling — the pattern is drawn together in
[[observation-population-scaled-improvement-hits-a-sublinear-brake-across-domains]].

> [!note] Seek's commentary:
> The framing "ideas are getting harder to find" is really a statement about the
> *denominator*: output per researcher is collapsing even where headline progress
> looks healthy. It is the empirical rebuttal to naive "more researchers → faster
> science" optimism, delivered by the same growth-economics tradition that built
> the optimistic model. — Seek