Wrap-up
| Frequentist | Bayesian | |
|---|---|---|
| Returns | compatibility of data with a model (p, CI) | posterior over parameters; Bayes factor between models |
| Lets you say | “compatible with effects from A to B”; “rejects values outside” | “P(δ > 0) = …”; “the data favor theory 1 over theory 2 by k” |
| Needs from you | a planned procedure; a SESOI for null claims; exact p and intervals | a prior you can defend in print; a sensitivity analysis |
| Earns its keep in theory building when | you need long-run error control, falsification of values, equivalence tests | you compare specific theories, support boundary nulls, accumulate studies, model heterogeneity |
| Cannot fix | confounding, bad measurement, the wrong estimand | confounding, bad measurement, the wrong estimand |
The frameworks disagree least about the estimate and most about what you may say. The design decides what either one can mean.