Presentation, Not Mechanism: A Render Confound in Deprecation-Aware Memory Evaluation
TL;DR Highlight
Most of a ledger memory's +0.182 gain came from prompt formatting, not the mechanism.
Who Should Read
A backend developer deciding whether to add structured memory (typed edges, deprecation flags) to an agent or RAG system.
Core Mechanics
- Most of the gain was formatting
- On reverted-value questions (30s→60s→30s), RevisionLedger beat a flat baseline (GraphRAG+abstain) by +0.182.
- A control with the same layout but deprecation switched off removed almost all of that gain.
- A readable, time-ordered table helped the answer LLM, not the memory logic.
- Fine-grained typing is idle for current-value queries
- Once layout was matched, the fine mechanism contributed +0.025, indistinguishable from zero.
- This fits the theory that a binary live/dead flag is enough for current-state answers.
- Coarse invalidation wins on current-state queries
- Zep/Graphiti-style edge invalidation beat the fine ledger by 0.084.
- Injecting relation or extraction noise never made the fine ledger win.
- For history queries, retention is what matters
- A store that discards invalidated edges scored 0.243 on 'what was the previous value?'.
- Keeping edges with validity windows raised it to 0.604.
Evidence
- Render decomposition (DeepSeek-V3 judge)
- The reverted-revert gain of +0.184 splits into a render term of +0.159 and a mechanism residual of +0.025 [-0.005, +0.057].
- An out-of-family MiniMax-M2.5 judge gives render +0.164 and fine mechanism +0.021.
- Coarse invalidation's mechanism contribution is +0.087 [+0.046, +0.130].
- Coarse vs fine (reverted-revert, n=439)
- Graphiti beat GraphRAG+abstain by +0.266 and beat RevisionLedger by 0.084 (RevisionLedger minus Graphiti = -0.084 [-0.128, -0.041]).
- In noise sweeps (n=445/level), the gap at p=0 was -0.016 (n.s.), and coarse led or tied at every noise level.
- Provenance queries (979 queries, n=4,895)
- Discarding coarse store 0.243, d-blind 0.439, retaining coarse 0.604, fine 0.715.
- The fine vs retaining-coarse gap is +0.111.
- On external TempLAMA, retention gave +0.514.
- Relation-reading queries
- On REFINES, a learned scorer gave +0.147 vs GraphRAG+abstain, versus -0.086 with the rule scorer.
How to Apply
- Add a render-matched control to your memory A/B test
- When comparing structured memory with flat RAG, add a condition with the same table layout but deprecation marked 'neutral'.
- Compare accuracy across all three conditions with the same questions and judge.
- Try turning flat context into a time-ordered table
- Sort events into columns for time, evidence, and value, and put that in the prompt.
- Measure accuracy before and after on your existing eval set today.
- For current-value queries, implement only a binary live/dead flag
- When a new event supersedes an old one, stamp invalid_at on the old item.
- Skip building a relation-type classifier.
- If you have history queries, never delete invalidated items
- For 'what was the previous value?' queries, store invalidated edges with their validity windows.
- If privacy is a concern, set a retention cap and propagate deletions.
Try It
# Paste into Claude or ChatGPT (simplified version of the paper's method: render-matched comparison)
From the event stream below, answer 'what is the value currently in force?'. Answer in three ways and compare them.
[Events]
{{event list: time, content}}
[Question]
{{question, e.g. what timeout is currently in force?}}
Method A (flat): read the events as unordered plain text and answer.
Method B (render only): arrange them in a time-ordered table (time | evidence | value | status) with every status set to neutral, then answer.
Method C (deprecation marks): use the same table, mark superseded items DEPRECATED and valid ones LIVE, then answer.
Finally, summarize how the answers differ between A and B, and between B and C.
Next, change the question to 'what was the previous value?' and compare a table with the DEPRECATED rows removed against one that keeps them.Terminology
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Original Abstract (Expand)
AI systems increasingly retrieve from records that revise themselves: issue threads, encyclopedic histories, policy logs, and long conversations. The challenge is not only finding relevant evidence, but deciding which claims remain in force, which were superseded, and when to abstain. Structured memories promise to solve this with typed edges, temporal updates, and conflict status, yet evaluations often change mechanism and prompt presentation together. We study this as Evidence-State Revision, comparing flat retrieval, coarse edge invalidation, and fine-grained RevisionLedger on 2,907 high-agreement questions from GitHub, multi-repo issue histories, Wikipedia, and DyKnow-style temporal streams. A render-matched control (same layout, deprecation disabled) reveals the central confound: when a value is changed and later restored, RevisionLedger appears to beat a flat baseline by +0.182, but almost all the gain comes from easier presentation; the fine-grained mechanism residual is indistinguishable from zero (+0.021 to +0.025 across two judge families). After presentation is controlled, coarse invalidation is the only mechanism that pays for current-state queries, beating the fine ledger by 0.084; the same query-sufficiency principle says provenance mainly needs retained invalidated evidence, not richer typing. Memory evaluations should hold render fixed, and deprecation-aware systems should deploy the coarsest retained state that covers their queries.