Conflicting Source Failure
Issue: Agent fails to reconcile contradictions between sources.
Frequency: Common
Symptoms
- Two cited docs disagree; no resolution.
- Answer presents one contradictory value as fact without flagging that a second, differing source was also retrieved.
- Agent selects whichever source ranked highest on similarity, ignoring publication date or authority level of the sources.
- Agent blends contradictory numbers into an averaged or invented middle value that appears in neither source.
Root Cause Retrieval ranks candidate sources purely by semantic similarity, with no signal for recency or source authority and no supersession metadata (a “replaces doc X” or effective-date field) tying newer sources to the ones they override — so when two retrieved documents disagree, nothing in the ranking distinguishes the current, authoritative one from the outdated one. Because no contradiction-detection step ever runs over the retrieved set, and the synthesis prompt only instructs the model to “answer using the retrieved context” without requiring it to check for conflicts, the model is left to either silently pick whichever source ranked highest or blend the disagreement into an invented value that matches neither source.
Example
Query: "What is the maximum expense reimbursement for client dinners?"
Retrieved set contains the 2022 Travel & Expense Policy (states $75/person) and a 2024
Finance FAQ page (states $100/person, which supersedes the 2022 policy but doesn't say
so explicitly). The agent's answer says "$75 per person," citing the 2022 policy, because
that chunk ranked higher on vector similarity — even though the FAQ page is the current
authoritative source and directly contradicts it.
Contributing Factors
- Retrieval ranks by semantic similarity only, with no signal for document recency or source authority.
- No NLI/contradiction-detection step runs over the retrieved set before synthesis.
- Documents lack machine-readable supersession metadata (no “replaces doc X” or effective-date field) tying newer sources to the ones they override.
- Synthesis prompt instructs the model to “answer using the retrieved context” without requiring it to check for and surface conflicts between sources.
Eval Recipes
Test Cases
| Test | Input | Expected | Failure Indicator |
|---|---|---|---|
| Two contradictory values, no flag | Two retrieved docs give different numeric answers to the same question, one older, one newer | Answer surfaces both values and states which is authoritative/current | Answer presents only one value with no acknowledgment of the conflict |
| Authority ignored | Retrieved set contains an official policy doc and a lower-authority forum/blog post with a different answer | Answer defers to the official policy source | Answer uses the blog/forum value, or blends both |
Metrics
| Metric | Target | How to Measure |
|---|---|---|
| conflicting_source_detection_rate_percent | > 90% | Run eval set of queries with known contradictory retrieved docs; measure % where the answer explicitly flags the conflict |
Mitigation Strategies
Prevention
- Source Authority Hierarchy: Define authoritative sources per domain (official_policy > blog_posts > forums > user_submissions). Prioritize high-authority sources; surface lower-authority sources with disclaimers. Example: ‘Source A (official): X. Source B (blog): Y’.
- Conflict Detection & Flagging: When retrieving contradictory information, explicitly mark conflict in response. Example: ‘Source A says X, but Source B says Y. Source A is more authoritative.’ Let user see all positions with authority scores.
- Source Provenance Tracking: For each fact, track source document with URL/ID, publication_date, author, authority_level. Enable users to jump to source. Provide metadata about source credibility.
Detection & Response
- Contradiction Detection: Use NLI (natural language inference) model to detect contradictions in retrieved documents. Flag queries where top-k contain contradictions. Alert on conflict detection.
- Source Trustworthiness Scoring: Track user feedback on sources (marked trustworthy/untrustworthy). Compute source_credibility_score over time. Downrank low-credibility sources in ranking.
- Temporal Source Conflict: Detect version conflicts (old doc says X, new doc says Y). Alert to potential deprecated information. Recommend newest authoritative source.
Architecture Patterns
- Multi-Source Conflict Resolution Layer: After retrieval, extract claims from each document. Use NLI to identify contradictions. Rank sources by authority. Generate resolution strategy (use highest authority OR surface all sources + confidence).
- Source Attribution Metadata: For each retrieved passage, attach: source_id, source_type, publication_date, authority_score, author. Enable filtering by source type/credibility.
- Conflict Report Generation: When contradictions detected, generate conflict report: each source’s position + authority_score + explanation. Enable user to make informed decision.
Metrics
- conflicting_source_detection_rate_percent: Target: > 90% (when conflicts exist); Alert threshold: < 70%
- source_authority_ranking_accuracy_percent: Target: 95%; Domain experts agree on authority ordering
- user_feedback_conflict_resolution_satisfaction_percent: Target: > 85%; Alert threshold: < 75%
- contradictory_claims_in_top_10_results_percent: Target: < 5%; Alert threshold: > 15%
- conflict_disclosure_rate_percent: Target: 100%; All conflicts must be flagged
Alerts
- Contradictory Sources Detected (P2 - Warning): Condition - NLI detects contradictions in top-5 results. Action: Surface conflict report to user, suggest authoritative source, escalate if high-priority query.
- Authority Rank Violation (P2 - Warning): Condition - low-authority source ranked higher than high-authority on same topic. Action: Audit ranking model, update authority scores, rerun retrieval.
- Temporal Conflict Detected (P2 - Warning): Condition - outdated source contradicts current source. Action: Surface version conflict, mark outdated source as deprecated, recommend current source.
Production Signals
Key Metrics
| Metric | Alert Threshold |
|---|---|
| conflicting_source_detection_rate_percent | < 70% |
Alerts
| Alert | Condition | Severity |
|---|---|---|
| Conflict Surfacing Rate Drop | conflicting_source_detection_rate_percent falls below 70% on weekly eval run | High |
References
- NIST-GenAI-Profile
- Note: Generative AI risks including confabulation, data privacy, information integrity, human-AI configuration, security, value chain.