Rubin's central device is the formula 1 β (1 β Ξ±)k, where k is the number of tests formally associated with a reported statistical inference β not the number of tests a researcher performed . This redefinition does the heavy lifting: once unreported tests are excluded from the reference set, most p-hacking scenarios leave each individual inference at Ξ±Individual = .050. The logic is internally consistent β the 20-sided-dice example for optional stopping is arithmetically sound β but note the hidden assumption: that researchers' inferences genuinely refer to study-specific null populations, not to broader substantive claims. If a p-hacked significant result is presented as evidence for a substantive hypothesis ("listening to 'When I'm Sixty-Four' makes people younger"), Rubin concedes this is a theoretical error β meaning the practice is still damaging, just re-labeled. That concession substantially dilutes the practical bite of the title.
The formula only produces inflation when a researcher makes a joint inference from k>1 tests without adjusting Ξ±Constituent β e.g., the .143 rate for k=3 shown above. Rubin's claim that this is "rare and easily resolved" depends on GarcΓa-PΓ©rez's finding that all observed multiple testing in 109 articles from two psychology journals (2021βJune 2022) consisted of single tests of individual hypotheses β a convenience sample from two selective journals that may under-represent forking-path inference.
Multiple independent simulations show systematic, sometimes large inflation β seemingly contradicting the title β though each involves outcome-dependent selection the paper would classify as theoretical-error territory: omission of random effects in mixed models raises average fixed-effects Type I error to 0.078 (max 0.274) ; selecting the smallest p-value across 72 analysis configurations inflates Type I error to ~0.23 in a trial-simulation study ; aggressive outlier filtering (MAD 2.0) yields FPR β 0.151 across 1,000,000 simulated RT analyses . Rubin's rebuttal would be that each involves rejection of a joint studywise null or theoretical misinterpretation β but that is precisely the move critics will find circular: any demonstrated inflation is re-classified as "irrelevant" because the affected inference is deemed atheoretical. The paper offers no prevalence data showing that theory-restricted inferences are what researchers actually make in p-hacking contexts .
Self-referential framing: Rubin cites his own work repeatedly (Rubin 2017a/b, 2020a/b, 2021a-c, 2022, 2024) as support, and his disclosed prior stance against preregistration creates an interpretive conflict-of-interest risk worth noting alongside the declared "no conflict." Citation imbalance: Simmons et al. (2011), the load-bearing target, is critiqued extensively but the abundant simulation literature documenting real-world inflation in genetics, diagnostics, and clinical trials is largely unaddressed β e.g., sex-stratified genetic meta-analysis shows cryptic-relatedness inflation , and response-rate misspecification in Simon designs inflates Ξ± from 0.0948 to 0.284β0.369 . What would falsify Rubin: a corpus-level study showing that reported inferences in p-hacked or outcome-selected contexts typically function as joint inferences over the unreported analysis family (e.g., via multiverse/specification-curve reanalysis of published papers showing the "selected" result is the only significant one among many plausible specifications). The multiverse-simulation literature already gestures in this direction.
Confidence: moderate β the logical analysis is sound; the empirical generalization ("not usually inflated") is untested.
Know what changed, what holds up, and what remains uncertain. Every Friday. No ads.