Francisco MinguezData & AI

Synthetic portfolio study

Published study

RAG Reliability study

A proprietary product direction for deciding when a RAG system should answer or defer, supported here by a synthetic answer/defer study.

This page documents a completed synthetic portfolio study with pre-registered evaluation criteria. Technical summary and public metrics are available here; source code and full artifacts remain private. Results apply only to the fixed benchmark described below.

Context

RAG Reliability is a proprietary product direction for deciding when a RAG system should answer or defer. Study v1 uses a synthetic Atlas Support Operations corpus with a frozen holdout so that evaluation, failure analysis and artifact integrity remain reviewable. Public results are summarised on this page; implementation details and full artifacts remain private. A controlled public demonstration of the Explorer is linked from this page.

Problem

High retrieval relevance alone does not guarantee that a system should answer. The evaluated pipeline must also handle conflicting lexical and dense rank-1 results, obsolete versus current documents, answerable queries, queries that require clarification, queries where abstention is appropriate, and the precision-coverage trade-off introduced by deferral.

Scope

  • Lexical BM25 baseline.
  • Dense MiniLM baseline.
  • Equal-weight hybrid reciprocal-rank fusion.
  • Status-aware current-first reranking.
  • Retrieval-consensus analysis.
  • Selective-risk analysis.
  • Signal-separability analysis.
  • Versioned v2 synthetic benchmark.
  • Frozen development/holdout split.
  • Top-1 gate pre-registration.
  • One-time holdout evaluation.
  • Deterministic artifact registry and SHA-256 evidence package.

Constraints

  • Synthetic benchmark only; no production traffic or real enterprise corpus.
  • 36-query holdout with fixed query composition.
  • Gate rules and success criteria were frozen before holdout evaluation.
  • Development and holdout were separated until the one-time evaluation.
  • Holdout status: unblinded. The holdout cannot be reused as unseen evidence.
  • Post-holdout gate tuning on this benchmark is prohibited.
  • Integrity regeneration is a reproducibility check only.
  • Results cannot support population-level or production deployment claims.
  • Source code, tests and full study artifacts are not publicly distributed.

Evaluation pipeline

  1. 01

    Lexical retrieval

    BM25 provides exact-term and token-overlap evidence.

  2. 02

    Dense retrieval

    Pinned MiniLM embeddings provide semantic retrieval evidence.

  3. 03

    Hybrid fusion

    Reciprocal-rank fusion combines lexical and dense rankings with equal weights.

  4. 04

    Status-aware reranking

    Current documents are prioritised over obsolete evidence.

  5. 05

    Top-1 consensus gate

    Answer only when BM25, dense and final current evidence share the same rank-1 document; otherwise defer.

Approach

  1. 01

    Establish baselines

    Define lexical BM25 and dense MiniLM retrieval baselines on the synthetic corpora.

  2. 02

    Evaluate hybrid retrieval

    Combine lexical and dense rankings with equal-weight reciprocal-rank fusion and apply status-aware current-first reranking.

  3. 03

    Analyse gate failures

    Examine consensus-gate failures and signal separability to understand when retrieval evidence supports an answer decision.

  4. 04

    Create frozen benchmark

    Build the versioned v2 synthetic benchmark with a fixed development/holdout split.

  5. 05

    Pre-register gate and criteria

    Freeze the top-1 consensus gate rules and three success criteria before any holdout access.

  6. 06

    Run holdout evaluation

    Execute the one-time unblinded holdout evaluation without changing the gate or thresholds.

  7. 07

    Consolidate evidence package

    Assemble deterministic JSON reports, a 33-artifact integrity registry and a versioned study package.

Deliverables

  • Versioned synthetic corpora.
  • Typed retrieval and evaluation implementation.
  • Deterministic JSON reports.
  • Pre-registration artifact.
  • One-time holdout report.
  • Final study report.
  • 33-artifact integrity registry.
  • Automated integrity and reproducibility checks.
  • Versioned study package with SHA-256 verification.

Technologies

  • Python
  • uv
  • pytest
  • BM25
  • sentence-transformers
  • all-MiniLM-L6-v2
  • reciprocal-rank fusion
  • SHA-256 artifact verification

Evidence

  • Pre-registered synthetic holdout result

    Frozen success criteria

    PASS 3/3

    All three criteria were frozen before holdout evaluation and passed without changing the gate or thresholds.

  • Synthetic holdout metric

    Answered-query precision

    17/20 = 0.850

    Required value was at least 0.75.

  • Synthetic holdout metric

    Answerable-query coverage

    17/22 = 0.773

    Required value was at least 0.70.

  • Synthetic holdout metric

    False-answer rate

    3/14 = 0.214

    Required value was at most 0.50 for queries expected to defer.

  • Descriptive synthetic holdout metric

    Decision accuracy

    28/36 = 0.778

    Accuracy was reported alongside precision, coverage and deferral errors; it was not a frozen success criterion.

  • Reproducibility evidence

    Evidence package

    33 registered artifacts across 12 stages

    The study is based on a reproducible internal benchmark over a synthetic support corpus. Public results are summarised here; source code and full artifacts remain private.

Limitations

  • Single synthetic benchmark with a small fixed 36-query holdout.
  • Fixed answer, clarify and abstain query balance.
  • No evidence about real support workloads or enterprise corpora.
  • No calibrated probability or confidence score is produced.
  • No generative-answer evaluation was performed.
  • Three false answers occurred on abstain queries.
  • Five answerable queries were deferred.
  • No generalisation evidence for other corpora, domains or languages.
  • The holdout is unblinded and cannot be reused as unseen evidence.
  • The study does not claim production validation or guaranteed answer correctness.

Production considerations

  • Independently designed real-corpus holdout with representative traffic and prevalence estimates.
  • Document lifecycle and status governance.
  • Retrieval and deferral monitoring with latency and cost measurement.
  • Access control and sensitive-data handling.
  • Human escalation paths for deferred or low-confidence queries.
  • Answer-generation evaluation beyond retrieval consensus.
  • Incident review and rollback procedures.
  • New confirmatory data for any modified gate before deployment.

Service relevance

  • RAG Reliability Audit of existing systems.
  • Answerability and abstention policy design.
  • False-answer and evidence-conflict analysis.
  • Synthetic and representative evaluation design.
  • Status-aware knowledge retrieval.
  • Evaluation protocol design.
  • Technical evidence and decision reporting.

Next steps

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