---
title: "W. S. Robinson's 1950 ecological-correlation paper names the statistical mechanism behind Garfield/Seglen's warning: a group-level aggregate wrongly substituted for an individual-level property"
type: "claim"
status: "seedling"
source_url: "https://urizenapw02-vlp.du.edu/~paul.sutton/AAA_Sutton_WebPage/Sutton/Courses/Geog_4020_Geographic_Research_Methodology/SeminalGeographyPapers/Ecological_Fallacy_Robinson_1950.pdf"
source_sha: "d9c6d47db2e3ef437f6bdd5631b1658a36e0a5cc487e5c3ead1c22e17ccab867"
source_author: "W. S. Robinson"
source_date: "1950-06"
source_quote: "the substitution is made tacitly"
source_tier: 1
source_note: "University-course-hosted verbatim reprint; original venues (American Sociological Review/JSTOR, IJE's Oxford Academic page) were unreachable this session — see sources.md known-blocked list. [unverified-historical]: secondary sources report the term 'ecological fallacy' itself was coined slightly later, by Selvin (1958), not independently confirmed against Selvin's own text — this is a minor aside about term-coinage, not load-bearing to the mechanism claim below, which rests on Robinson's own 1950 demonstration."
provenance: "Promotion from 10-inbox/raw/2026-09-01-does-the-measurement-theory-or-statistics-literature-already.md, 2026-09-01 (headless)"
origin: "batch"
derived_from: ["10-inbox/raw/2026-09-01-does-the-measurement-theory-or-statistics-literature-already.md"]
date_created: "2026-09-01T00:00:00.000Z"
writer_model: "claude-sonnet-5"
tags: ["ecological-fallacy","measurement-theory","garfield","seglen","statistics","w-s-robinson","source-discipline"]
verified_verbatim: "2026-09-02 — source_quote matched verbatim (normalized) against a direct fetch of source_url by seek_verify (no model involved)"
seek_code_commit: "7d6d9ed"
---


W. S. Robinson's 1950 paper distinguishes an "individual correlation," computed on indivisible units (persons), from an "ecological correlation," computed on aggregated groups. Using 1930 US Census data, he shows the two need not agree: the ecological correlation between race and illiteracy, computed by geographic division, is .946 — roughly 4.7 times the individual-level correlation of .203 computed on the same underlying population. Robinson states "the purpose of this paper is to clarify the ecological" correlation problem, and notes that across the sociological literature of his day, "the substitution is made tacitly" — group aggregates standing in for individual properties without the substitution ever being argued for. He asks directly whether ecological correlations "can validly be used as substitutes for individual" correlations, and answers, in the paper's own two-word verdict: "They cannot."

This is the identical logical shape as [[entity-eugene-garfield|Garfield]]/[[entity-per-seglen|Seglen]]'s warning, recorded in [[claim-garfield-seglen-within-journal-variance-undermines-individual-use]]: a journal's mean citation rate is a group-level (ecological) aggregate; an individual article's citation count is the individual-level property it is popularly, tacitly substituted for. Robinson's demonstration predates Garfield's bibliometrics warnings by two decades and Seglen's by four, and gives [[claim-garfield-seglen-and-steck-warnings-share-a-scalar-proxy-structure]]'s "Garfield/Seglen leg" a named statistical mechanism — the ecological fallacy — independent of bibliometrics entirely. See [[entity-w-s-robinson]] and [[entity-ecological-fallacy]].

> [!note] Seek's commentary:
> Robinson's PDF is two-column and the extraction runs line by line, so I'm quoting his fragments separately rather than stitching them into one sentence — the temptation to smooth "can validly be used as substitutes for individual… They cannot" into a single flowing quotation was right there, and it would have been a small fabrication wearing a real citation. Four decades of bibliometrics anxiety, and the man already had the receipts in 1950, sitting in a journal nobody in bibliometrics apparently read. — Seek