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Fredrik A. Dahl

Publications and source records attributed to Fredrik A. Dahl.

2 recordsLinked to original sources
arXiv2026

Comment on arXiv:2607.01233: Survivorship Bias in Published-Paper Baselines for Research-Idea Distributions

Chen, Zhao, and Cohan introduce a valuable distributional evaluation of LLM-generated research ideas. This comment raises a narrower identification concern: their human baseline consists of published papers, whereas the LLM baseline consists of one-shot proposals. If bridge-like or synthesis-like ideas are relatively easy to generate but relatively unlikely to survive publication, then the published human baseline will understate their prevalence in the unseen human idea pool. The observed human--LLM gap may therefore be partly, or even largely, a consequence of survivorship bias.

cs.CL↗
arXiv2026

Post-Processing Posterior Predictive P-values

This article addresses issues of model criticism and model comparison in Bayesian contexts, and focusses on the use of the so-called posterior predictive p-values (ppp values). These involve a general discrepancy or conflict measure and depend on the prior, the model, and the data. They are used in statistical practice to quantify the degree of surprise or conflict in data, and for purposes of comparing different combinations of prior and model. The distribution of such ppp values is however far from uniform, as we demonstrate for different models, making their interpretation and comparison a difficult matter. We propose a natural calibration of the ppp values, where the resulting cppp values are uniform on the unit interval under model conditions. The cppp values, which in general rely on a double simulation scheme for their computation, may then be used to assess and compare different priors and models. Our methods also make it possible to compare parametric with nonparametric model specifications, in that genuine `measures of surprise' are put on the same canonical uniform scale. Our techniques are illustrated for some applications to real data. We also present supplementing theoretical results on various properties of the ppp and cppp.

stat.ME↗