Economics, Evolving1776–present

Endogenous growth · idea production · artificial intelligence

Romer After
the Machine

In his 1990 model, Paul Romer made technological change the result of purposeful research. The machine now enters that idea factory—but it does not make proof, absorption, or diffusion free.

A model can generate a thousand hypotheses before breakfast. Growth still arrives one validated idea at a time.

Research cut-off · 5 August 2026Interactive reconstruction · model outputs are illustrative, not forecasts

Romer 1990 · reconstructed

The loop that moved technology inside economics

Select a stage. Romer separates the reusable design from the rival object built with it, then lets the accumulated stock of designs make tomorrow's research more productive.

Research sector

Purposeful effort

Research human capital combines with the inherited knowledge stock. Existing ideas are both an input into discovery and the record of solved problems.

New knowledge feeds back into the next research cycle

The AI extension

Four parameters decide whether the curve bends

Capability is only one input. Research output is shaped jointly by breadth, relative performance, the O-ring structure of the process, and the rate at which plausible output becomes trusted knowledge.

γ

Task coverage

How much of the complete research chain can the machine perform at the required quality?

M

Machine productivity

How large is the cost, speed, or quality advantage on tasks that are technically feasible?

θ

Bottleneck strength

Can exceptional performance on one stage substitute for weak performance elsewhere?

V

Validation and absorption

What share of generated output survives proof, engineering, governance, adoption, and diffusion?

AI research funnel · illustrative

Generation is not yet knowledge

AI can widen the top of the funnel. The growth effect is governed by throughput at the narrowest complementary stage—not by proposal volume.

Shadow price moves to

Experiment and replication

  1. Stage 01

    Generated candidates

    Starting candidate pool

    1,000

    100% of initial

  2. Stage 02

    Screened proposals

    58% pass-through from prior stage

    580

    58% of initial

  3. Stage 03Binding drop

    Experiments / simulations

    53.4% pass-through from prior stage

    310

    31% of initial

  4. Stage 04

    Validated knowledge

    58.1% pass-through from prior stage

    180

    18% of initial

  5. Stage 05

    Adopted innovation

    55.6% pass-through from prior stage

    100

    10% of initial

10%

Final yield

900

Candidates filtered

53.4%

Binding pass-through

Illustrative conversion from 1,000 machine-generated candidates

Live model · not a forecast

Run the idea factory

The same machine can produce a modest level shift or a persistent acceleration. The difference lies in task coverage, complementarity, validation, and how strongly new knowledge raises future research productivity.

1.61×

effective research tasks

138

knowledge index · year 40

0.81%

annualized knowledge growth

46%

candidate survival

0Year 40145100AI-assisted validated knowledgeNo AI task coverage

Candidate flow

2.31

plausible additions per model period

Validation gap

1.25

candidates that do not enter usable knowledge

Continue into the full argument

The Idea Factory Meets the AI Factory

The essay reconstructs Romer, extends the research production function, reviews the newest evidence, maps the expanding idea space, separates levels from growth rates, and proposes a falsifiable empirical programme for validated knowledge.

Read the essay