Methodology principle. Code does not become law because it exists, and a professional judgment does not become a DCWP requirement because an auditor prefers it. Our methodology classifies controls so each conclusion can be traced to its proper authority.
Methodology classification
- LL144 / DCWP required — obligations prescribed by statute or rule.
- LL144 / DCWP permitted — choices expressly permitted by the rule, such as the less-than-2% category exclusion.
- Professional auditor methodology — judgments necessary to perform a defensible audit where the rule does not prescribe every statistical decision.
- Lexara internal control — evidence, provenance and quality controls used to make the work reproducible.
Continuous-score methodology — METH-1.3.0
For supported score-based AEDTs, the implemented method uses the median of the approved full sample and a strict-above-median scoring event. Category scoring rates are compared with the highest exact eligible scoring rate.
sample median = median(all included numeric scores)
scoring rate = count(score > median in group) / group count
impact ratio = group scoring rate / highest eligible scoring rate
Display rounding does not control comparator identity.
Binary selection / classification — BINSEL-1.0.0
For supported move-forward decisions and binary classifications, selection rates are calculated against an approved denominator population with explicit source-outcome mapping. Binary classification preserves each configured class as its own calculation target rather than silently treating one outcome as the only relevant class.
selection rate = target count / approved group denominator
impact ratio = group selection rate / highest eligible selection rate for that target
Comparator construction
The comparator is based on the highest exact eligible rate. Exact ties remain part of the comparator set. Alphabetical order, group size or UI display rounding are not used to break ties.
Demographic controls
Lexara uses supplied demographic information and explicit mapping controls. We do not infer or impute protected characteristics. Known but non-analytical values are preserved as controlled states rather than silently reassigned.
The less-than-2% rule
DCWP permits an independent auditor to exclude a category that represents less than 2% of the data used for the audit from required impact-ratio calculations. Lexara calculates the relevant share but does not make the exclusion automatically; it remains an explicit professional auditor decision.
What the methodology does not claim
The calculation layer does not automatically issue legal or discrimination conclusions. We do not label an AEDT “bias free,” “compliant,” “non-compliant,” “legal,” “illegal,” “pass” or “fail” solely from a calculated impact ratio.
Evidence and reproducibility
The wider Lexara audit platform separates source evidence, structural intake, provenance, calculation, professional review and reporting. This is designed to preserve the path from source data to final reported metrics and reduce undocumented transformations.
Methodology versions referenced on this page are the currently implemented baselines documented in Lexara's LL144 audit platform as of September 17, 2026.