Every mark is the same quantity: conditional standard error at the decision point, in logits. Metrology and the familiar tests share one frame.
XLNC / AIM 0.07 design target (PILOT) 10:1 gold 0.10 4:1 good 0.25 Six Sigma 0.33 (Westgard)
Conditional SE at the decision point (logits, k=1). Tight on the left, wide on the right.
What this means: every mark is the same quantity, conditional standard error at the decision point, so a lower bar is a tighter measurement. XLNC 0.07 sits tighter than even the metrology gold 10:1 reference.
GMAT is held: no like-for-like published precision figure exists, so it is not plotted.
Physical instruments (vernier 0.02 mm, micrometer 0.01 mm, gauge blocks, SI metre) define minimum precision as a stated floor in their native units. The metrology discipline, a stated decision-quality uncertainty floor, is what the gold, good, and Six Sigma anchors carry onto this ruler. AIM is not a NIST or ISO standard; the claim is that the discipline is the same. Test names are trademarks of their owners; XLNC is not affiliated with, endorsed by, or sponsored by any listed organization. Crosswalk: logit = 2 x (SE/SD); within-sample SD is about 1 MHC stage, about 2 logits (explicit modeling assumption).
Certified 07-23 figures only. Axis measurand is conditional standard error at the decision or cut point, in logits, k=1. Internal-consistency alpha, IRT marginal reliability, split-half, and composite reliability are not on this ruler. SAT and WAIS-IV use the certified 07-23 test-retest fallback. GMAT is held because no like-for-like published precision figure exists. This is not a claim that XLNC is better than any named test.
| Instrument | Conditional SE (logits) | What is plotted |
|---|---|---|
| XLNC / AIM | 0.07 | 0.07 is the XLNC / AIM design target in validation. PILOT. |
| ACT | 0.34 | conditional SE at the cut |
| WAIS-IV | 0.40 | test-retest |
| SAT | 0.53 | test-retest |
| GRE Quant at 150 | 0.55 | conditional SE at the cut |
| GRE Verbal at 150 | 0.64 | conditional SE at the cut |
| USMLE Step 3 | 0.67 | global SEM on a known score SD |
| USMLE Step 2 CK | 0.80 | global SEM on a known score SD |
