Ablation Study

document recall (Avg R@10) when one design choice is removed · bar length = the value on a 0–100 axis

hierarchy in the index · does the Doc card need it?

body text only
81.2
+ titles, concatenated
84.6
separate hierarchy field
88.6

hierarchy as an explicit signal: +7.4 over no hierarchy

two-stage routing · is coarse-to-fine needed?

sections only
76.1
documents only
87.7
docs → sections
88.6

skipping the document stage collapses recall (−12.5)

search scope · does narrowing help at all?

whole corpus, no routing
81.0
candidate docs only
87.9
+ anchor subtree
88.6

routing itself is worth +7.6

score signals · does each one earn its place?

keywords only
87.6
+ text embeddings
88.2
+ visual embeddings
88.6

each signal adds a little · the visual one completes it

No latency or cost experiment in the paper · the efficiency case rests on zero query-time LLM calls (by design) and the budget robustness of the previous slide; offline DHP indexing overhead is acknowledged as a limitation, without numbers
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