The paper is a narrative conceptual review arguing that correlation is descriptive while causation is explanatory and theory-driven, and that credible causal claims require identification strategies: randomized controlled trials, instrumental variables, difference-in-differences, and explicit causal frameworks such as the Rubin potential-outcomes model and Pearl's structural causal models . The core logic is sound and matches the modern causal-inference consensus. Illustrations are classic and accurate: the Berkeley 1973 admissions Simpson's paradox case , and compulsory-schooling IV designs for education-earnings estimates .
It is a non-systematic narrative review: no PRISMA-style search protocol, no formal quality appraisal, and zero original empirical analysis — limitations the author partially acknowledges . Several claims are under-specified relative to the modern literature. The paper reports IV returns to education "around 3%" versus "10%" OLS without citing uncertainty; contemporary IV work stresses that weak instruments bias 2SLS toward OLS and that jackknife/LIML-type estimators achieve far better coverage (2SLS coverage as low as 0.31 versus ~0.94-0.97 for JIVE/LIML in many-weak-instrument simulations) . The treatment of Granger causality as a partial solution is correct but shallow — the paper notes it "can help disentangle" macro relationships without discussing that Granger causality is predictability, not structural causation, a distinction vivid in oil-price data where Brent and WTI correlate strongly (R² = 0.873) yet show no Granger causality in either direction .
The review omits several topics its own argument depends on: sensitivity analysis for unmeasured confounding, modern DiD corrections for staggered adoption, and design-based falsification tests (placebos, manipulation checks). It also skips publication bias entirely, despite strong evidence that editorial intervention measurably shifted test-statistic distributions in health economics (a ~18 percentage-point drop in significant results after an editorial statement, though with very low R² and acknowledged tentativeness) — highly relevant since correlation-based reporting bias is a mechanism by which spurious associations enter the literature. Falsification note: the paper's central thesis is essentially unfalsifiable as stated (it is a tautological methodological maxim), which is appropriate for pedagogy but limits scientific content; evidence that covariate-adjusted regression consistently recovered causal effects under known unmeasured confounding would be the relevant counterexample, and none exists in the supplied sources. Confidence: high that the review is accurate and pedagogically useful; low on novelty and scientific contribution beyond didactics.
Know what changed, what holds up, and what remains uncertain. Every Friday. No ads.