If method selection can't be explained step-by-step, it can't be trusted at scale. Deterministic rule traces turn statistics from 'expert opinion' into a transparent decision system.
In many teams, 'choose the right test' is treated as craft knowledge. The output might be correct — but the reasoning is hidden. Reviewers then evaluate confidence, not logic.
A black-box method picker creates three downstream failures: review risk where methods are challenged because assumptions are not documented; mentorship drift where juniors learn recipes, not reasoning; and governance gaps where decisions can't be audited or standardised across studies.
A rule trace is a human-readable explanation of how the engine arrived at a recommendation — including the assumptions it checked, the branches it rejected, and the conditions that triggered the final selection.
Reviewers don't just want 'the right test.' They want to see that you respected assumptions, recognised design constraints, and chose a defensible path. A trace makes that visible — instantly.
Study intent and design: association vs prediction vs comparison; independent vs paired; cross-sectional vs longitudinal.
Variable types: continuous, binary, ordinal, count, time-to-event; number of groups; repeated measures flags.
Assumption checks and fallbacks: normality, variance equality, expected cell counts, proportional hazards — and what happens if they fail.
Final selection with rationale: why this method was chosen over the alternatives, with explicit reference to the decision branches taken.
When the trace is visible, a senior reviewer's job shifts from 'Is this right?' to 'Is this well-reasoned?' That's a fundamentally more productive conversation — and one that transfers knowledge rather than just issuing verdicts.
At the institutional level, standardised traces create a reusable library of defensible method selections. New researchers don't start from scratch — they start from a documented precedent.
Ayati builds decision systems that embed these principles — audit-ready, explainable, and governance-ready.