Averageism vs Marginalism in Research

Updated: 2026.04.14 8H ago 1 sources
Social sciences can describe phenomena two ways: by averages (what a typical member or aggregate looks like) or by margins (what one additional unit changes). The article argues modern empirical practice—and machine learning—tilts researchers toward estimating credible causal or predictive averages without checking whether those estimates map to the marginal quantities that older theory prized. — If researchers stop asking whether their estimates capture the theoretically relevant marginal effects, policy decisions may be driven by well‑identified correlations or predictions that don't have the causal meaning policymakers assume.

Sources

Hollis Robbins on Average vs. Marginal
Arnold Kling 2026.04.14 100% relevant
Hollis Robbins’ gloss of Tyler Cowen’s book, the Solow example (factor shares as averages vs marginal product), and the book’s explicit claims about machine learning dropping interpretable theoretical scaffolding.
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