AB.A model is useful only when its limits are measurable.All projects

Data Science

FaultForge

A model-evaluation workbench that measures how classification pipelines behave under missingness, noise, distribution shift, and other real-world stresses.

Robustness TestingBootstrap EvidenceCalibrationModel Reliability
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FaultForge interface

Why it matters

Replaces a single accuracy score with reproducible evidence showing where a model remains reliable and where it does not.

My role

Data scientist, model-evaluation designer, and solution developer

  1. 01Defined reproducible stress plans, metric guards, deployment ranges, adequacy rules, and confirmed breaking-point logic.
  2. 02Implemented repeated-seed evaluation, paired bootstrap evidence, calibration, prediction margins, flip diagnostics, PSI screening, and comparable version ranking.
  3. 03Designed evidence outputs that distinguish pass, performance failure, execution failure, flakiness, and inconclusive results instead of forcing false certainty.
01

Evaluation question

Strong held-out accuracy does not reveal when a classifier stops working. FaultForge deliberately introduces missingness, numerical noise, distribution shift, categorical drift, unseen categories, prevalence change, and invariance probes.

02

Repeated evidence

Every severity level runs across multiple deterministic seeds and reports mean, standard deviation, minimum, and maximum. Conservative guards use mean minus standard deviation against user-defined requirements.

03

Confirmed limits

A failure becomes a breaking point only when all later severities also fail. Isolated drops are marked flaky, and the result is reported as an interval because a discrete sweep cannot prove an exact threshold.

04

Metrics & uncertainty

The baseline includes accuracy, balanced accuracy, recall, precision, F1, ROC-AUC, PR-AUC, Brier score, and confusion matrices. Paired class-stratified bootstrap evidence prevents unsupported drops from being promoted as confirmed failures.

05

Diagnostics

Calibration, probability margins, near-threshold risk, per-row prediction flips, curve-retention summaries, compound-stress ablations, and PSI feature-drift rankings help explain how degradation appears.

06

Decision policy

Deployment ranges prevent models from being penalized for irrelevant conditions. Fewer than 30 minority-class examples produces an inconclusive result, while fewer than 10 is rejected, keeping promotion evidence honest.

07

Reproducibility

Immutable model and dataset fingerprints, full experiment configurations, deterministic seeds, version comparison rules, and standalone JSON/HTML evidence preserve the relationship between a decision and its exact inputs.

Technical implementation

How the solution was built.

Each layer connects an implementation choice to the decision or workflow it supports.

06 layers
LayerImplementationOperational purpose
Experiment definitionVersioned model artifacts, dataset fingerprints, target semantics, stress plans and metric guardsMake every evaluation reproducible and tied to the exact model and data used
Stress generationMissingness, numerical noise, distribution shift, categorical drift, unseen categories and prevalence changeMeasure behaviour under realistic data-quality and population changes
Repeated evaluationDeterministic multi-seed trials with mean, standard deviation, minimum and maximum summariesSeparate stable degradation from one-off variation
Statistical evidencePaired class-stratified bootstrap intervals and conservative guard valuesAvoid declaring failure when the observed difference is not adequately supported
DiagnosticsCalibration, confusion matrices, probability margins, prediction flips, PSI and compound-stress ablationsExplain how and where model behaviour changes
Decision outputPass, failure, flaky, inconclusive and execution-failure states with JSON and HTML evidenceTranslate evaluation results into reviewable promotion decisions