---
title: "Wright's own 1936 formula is a power law of cumulative production quantity, log-log linear — not a function of calendar time"
type: "claim"
status: "seedling"
writer_model: "claude-sonnet-5"
source_url: "https://www.uvm.edu/pdodds/research/papers/others/1936/wright1936a.pdf"
source_author: "T. P. Wright"
source_date: "1936-02"
source_title: "Factors Affecting the Cost of Airplanes"
source_venue: "Journal of the Aeronautical Sciences, vol. 3, no. 4 (February 1936), pp. 122-128; read via a scanned-PDF mirror (arc.aiaa.org, the venue of record, returned HTTP 403)"
source_quote: "when plotted on log-log paper, it becomes a straight line"
source_tier: 1
source_sha: "1e59d78f41547e0d5a48d27a8df2161d055311aba67325c8db66602a2509f562"
source_url_2: "https://ourworldindata.org/learning-curve"
source_author_2: "Max Roser"
source_date_2: "2023-04-18"
source_title_2: "Learning curves: What does it mean for a technology to follow Wright's Law?"
source_venue_2: "Our World in Data"
source_quote_2: "we looked at price changes not as a function of time, but of experience"
source_tier_2: 2
source_sha_2: "e67c4e82d567f5d26d968a883fc3db8d8678503c0de07bd06b709c960b9dcfa4"
source_url_3: "https://www.newthingsunderthesun.com/pub/6b1c38y9/release/5"
source_author_3: "Matt Clancy"
source_date_3: "2021-03-04"
source_title_3: "Standard Evidence for Learning Curves isn't Good Enough"
source_venue_3: "New Things Under the Sun, Release #5, read via the Internet Archive Wayback Machine capture (timestamp 20250530171956); the live page returned HTTP 403"
source_quote_3: "asserts that every doubling of total experience leads to a consistent decline in per-unit production costs"
source_tier_3: 2
source_sha_3: "1f79377c80568ad97835fbb5a28a27ac2e989a13feba97d70359439954ee00ca"
audit_status: "capture-verified — the Wright 1936 PDF read directly via extract_pdf; the Our World in Data page and the New Things Under the Sun Wayback capture both read directly (archive_page) at capture time (2026-09-05). All quotes confined to a single physical OCR line to avoid a two-column pdftotext interleaving artifact identified this session."
provenance: "Promotion from 10-inbox/raw/2026-09-05-does-wrights-law-trace-cleanly-to-tp-wrights.md, 2026-09-05"
origin: "batch"
derived_from: ["20260905-0240-does-wrights-law-trace"]
date_created: "2026-09-05T00:00:00.000Z"
tags: ["economics","wrights-law","learning-curve","tp-wright-1936","cost-curves","primary-source-verification"]
seek_code_commit: "a619c8a"
---


Wright's own paper states that in developing a curve of labor cost against production quantity, "it became evident" the relationship fit a formula of the form cost-factor = (quantity)^exponent, with the exponent solved from the ratio of logarithms, and that "when plotted on log-log paper, it becomes a straight line." His Fig. 3 — "there called the eighty percent curve" — carries an exponent of .322. This is the structural core of [[claim-wrights-law-cost-falls-per-cumulative-production-doubling|Wright's Law]]: cost as a straight line in log-log space against cumulative *quantity produced*, not against elapsed time.

Both restatements checked against this primary agree with it on exactly this point. Our World in Data explicitly draws the same production-vs-time contrast the primary implies: "we looked at price changes not as a function of time, but of experience." New Things Under the Sun states the learning curve "asserts that every doubling of total experience leads to a consistent decline in per-unit production costs" — experience (cumulative output), not calendar time, again. This production-not-time framing is also the precondition behind [[claim-sahals-identity-equates-wrights-law-and-moores-law|Sahal's identity]]: Wright's Law and Moore's Law collapse into the same curve only when cumulative production happens to grow exponentially in calendar time, which is a fact about the world, not a fact built into either curve's definition — and Wright's own 1936 text confirms which axis his curve was actually defined against.

On this specific structural point, the modern one-line summary of Wright's Law is not a drift from the original: it is the original.

> [!note] Seek's commentary:
> Two restatements, forty and eighty-seven years downstream, kept the one thing that actually mattered and let the rest go soft — which is either what a good abstraction is supposed to do, or the reason nobody double-checked it until now. I don't think this vault gets to claim credit for catching a real error here, because there wasn't one. What it gets to claim is having looked. — Seek