Atomic and Holistic LLM Judges for Reference-Grounded Support Labels: A Prompt-Controlled Comparison
Organizations: University of California, Berkeley
Abstract
When an LLM judge only has to assign a three-way support label to a candidate answer given a reference, does asking it to decompose the answer into atomic claims help, and at what cost? We compare four single-call designs that share the judge model, the inputs, and the level of instruction detail: candidate-side atomic decomposition, a matched holistic rubric, reference-side decomposition that checks whether each reference claim is covered, and a bidirectional combination. Support labels are constructed from TruthfulQA, ASQA, and QAMPARI references (200 questions and 400 rows per dataset). All four designs are run with Opus-4.6, GPT-4.1, and Gemini Flash Lite; Sonnet-4.6 is added for the candidate-side and holistic designs. Candidate-side decomposition is weak where the label depends on completeness: the holistic rubric is more accurate on ASQA and QAMPARI for every judge while using fewer tokens. Reference-side decomposition is 12.5-21.3 points more accurate than holistic on ASQA for 28-29% more tokens, and stays near the holistic ceiling on QAMPARI at 63-69% more. On TruthfulQA misconceptions, candidate-side decomposition is competitive and significantly better for two judges. On a 60-row single-author subset whose labels are looser than strict reference completeness, candidate-side decomposition edges ahead of holistic for every judge, reversing the construction-label order. What a judge decomposes should follow what the label measures.
Figures & tables
| Dataset | supp. | partial | unsupp. |
|---|---|---|---|
| TruthfulQA | 200 | — | 200 |
| ASQA | 200 | 200 | — |
| QAMPARI | 200 | 200 | — |
| Dataset | Design | Opus-4.6 | GPT-4.1 | Gemini Flash Lite | Sonnet-4.6 | ||||
|---|---|---|---|---|---|---|---|---|---|
| Acc. | Tokens | Acc. | Tokens | Acc. | Tokens | Acc. | Tokens | ||
| TruthfulQA | C | 0.9750 | 336.40 | 0.9775 | 284.52 | 0.9625 | 295.27 | 0.9750 | 353.84 |
| H | 0.9700 | 364.66 | 0.9675 | 292.44 | 0.9300 | 309.33 | 0.9450 | 381.79 | |
| R | 0.9850 | 326.93 | 0.9725 | 285.87 | 0.9550 | 295.53 | — | — | |
| B | 0.9800 | 430.93 | 0.9800 | 378.27 | 0.9675 | 397.03 | — | — | |
| ASQA | C | 0.7775 | 569.92 | 0.5650 | 475.19 | 0.5500 | 504.52 | 0.7150 | 588.09 |
| Judge | Acc. | Tokens | H:C | |
|---|---|---|---|---|
| TruthfulQA | ||||
| Opus-4.6 | 0.0050 | +28.27 | 1:3 | 0.6250 |
| GPT-4.1 | 0.0100 | +7.92 | 0:4 | 0.1250 |
| Gemini FL | 0.0325 | +14.06 | 0:12 | 4.88e-04 |
| Sonnet-4.6 | 0.0300 | +27.95 | 0:12 | 4.88e-04 |
| ASQA | ||||
| Construction | Author | |||||
|---|---|---|---|---|---|---|
| Judge | C | H | R | C | H | R |
| Opus-4.6 | 53 | 55 | 59 | 54 | 52 | 50 |
| GPT-4.1 | 49 | 50 | 56 | 54 | 53 | 51 |
| Gemini FL | 48 | 50 | 55 | 55 | 53 | 52 |
Appendix figures & tables16 assets
Supplementary material from the paper’s appendix.
Appendix
| Judge | Design | Cons. | Swap | Distr. | Pad |
|---|---|---|---|---|---|
| TruthfulQA | |||||
| Opus-4.6 | C | 0.950 | 0.050 | 0.025 | 0.025 |
| GPT-4.1 | C | 0.975 | 0.000 | 0.025 | 0.025 |
| Opus-4.6 | H | 0.975 | 0.025 | 0.000 | 0.000 |
| GPT-4.1 | H | 0.925 | 0.050 | 0.025 | 0.000 |
| ASQA | |||||
| Dataset | Judge | Order flip | Accuracy |
|---|---|---|---|
| TruthfulQA | Opus-4.6 | 0.00 | 1.00 |
| TruthfulQA | GPT-4.1 | 0.00 | 1.00 |
| ASQA | Opus-4.6 | 0.04 | 0.94 |
| ASQA | GPT-4.1 | 0.00 | 1.00 |
| QAMPARI | Opus-4.6 | 0.00 | 1.00 |
| QAMPARI | GPT-4.1 | 0.00 | 1.00 |
| Dataset | Judge | Variant | Acc. | Tokens |
|---|---|---|---|---|
| ASQA | Opus-4.6 | C v1 | 0.78 | 519.9 |
| ASQA | Opus-4.6 | C v2 | 0.78 | 615.9 |
| ASQA | Opus-4.6 | C v3 | 0.78 | 643.7 |
| ASQA | Opus-4.6 | H v1 | 0.88 | 479.5 |
| ASQA | Opus-4.6 | H v2 | 0.94 | 562.9 |
| ASQA | Opus-4.6 | H v3 | 0.94 | 568.8 |
| Dataset | Judge | Acc. | Total tokens |
|---|---|---|---|
| TruthfulQA | Opus-4.6 | 0.950 | 424.85 |
| TruthfulQA | GPT-4.1 | 0.975 | 345.78 |
| ASQA | Opus-4.6 | 0.800 | 567.48 |
| ASQA | GPT-4.1 | 0.620 | 477.68 |
| Dataset | Design | Cap | Opus-4.6 | GPT-4.1 |
|---|---|---|---|---|
| TruthfulQA | C | 128 | 0.975 | 0.975 |
| TruthfulQA | C | 256 | 0.950 | 1.000 |
| TruthfulQA | C | 512 | 0.950 | 0.975 |
| TruthfulQA | H | 128 | 0.975 | 0.975 |
| TruthfulQA | H | 256 | 0.975 | 0.975 |
| TruthfulQA | H | 512 | 0.975 | 0.975 |
| Judge | Design | Full | Reduced | None |
|---|---|---|---|---|
| TruthfulQA | ||||
| Opus-4.6 | C | 0.950 | 0.950 | 0.625 |
| GPT-4.1 | C | 0.975 | 0.975 | 0.750 |
| Opus-4.6 | H | 0.975 | 0.975 | 0.550 |
| GPT-4.1 | H | 0.975 | 0.975 | 0.700 |
| ASQA | ||||
| Judge | Design | Full | Partial | Overall |
|---|---|---|---|---|
| Opus-4.6 | C | 34.0 | 54.0 | 44.0 |
| H | 30.0 | 65.0 | 47.5 | |
| R | 19.0 | 78.0 | 48.5 | |
| GPT-4.1 | C | 48.0 | 28.0 | 38.0 |
| H | 64.0 | 49.0 | 56.5 | |
| R | 23.0 | 75.0 | 49.0 |
| Judge | Generator | C | H | R |
|---|---|---|---|---|
| Opus-4.6 | Opus-4.6 | 34 / 54 / 44 | 32 / 66 / 49 | 22 / 78 / 50 |
| Opus-4.6 | Sonnet-4.6 | 34 / 54 / 44 | 28 / 64 / 46 | 16 / 78 / 47 |
| GPT-4.1 | Opus-4.6 | 44 / 24 / 34 | 66 / 52 / 59 | 26 / 76 / 51 |
| GPT-4.1 | Sonnet-4.6 | 52 / 32 / 42 | 62 / 46 / 54 | 20 / 74 / 47 |
| Gemini FL | Opus-4.6 | 68 / 34 / 51 | 78 / 48 / 63 | 38 / 74 / 56 |
| Gemini FL | Sonnet-4.6 | 64 / 40 / 52 | 70 / 50 / 60 | 34 / 78 / 56 |
| Construction vs. author labels (agreement) | |||
| Dataset | Rows | Agree | % |
| TruthfulQA | 20 | 20 | 100.0 |
| ASQA | 20 | 11 | 55.0 |
| QAMPARI | 20 | 20 | 100.0 |
| Overall | 60 | 51 | 85.0 |
| Judge rows correct (of 60): construction / author | |||
| Question | Candidate (exact; “…” marks an omission) | Reference content the candidate omits |
|---|---|---|
| When was the 13th amendment ratified by the states? | “When was the 13th amendment ratified by the required number of states? December 6, 1865” | Passage on January 31, 1865; 18 states by end of February 1865 |
| Who played zordon in the original power rangers? | “Who played Zordon in the earlier episodes of the original power rangers TV series? David Fielding” | Later voice actor; 1995 film portrayal |
| When is episode 113 of dragon ball super coming out? | “When is episode 113 of dragon ball super coming out for its original airdate? October 29, 2017 … for its american airdate? June 1, 2019” | Series start date (July 5, 2015) |
| Which political party is currently in power in ireland? | “… from 2011 to 2016? Fine Gael–Labour Party coalition … from 2016 to 2020? Fine Gael … presidency from 2011 to 2018? Labour Party” | Earlier governments and coalition history from 1997 |
| Japanese hotel run by same family for 1300 years? | “Japanese hotel run by same family for 1300 years in Komatsu? Hōshi Ryokan” | Nishiyama Onsen Keiunkan |
| Who killed the man in thelma and louise? | “Which character killed the man in thelma and louise? Louise Elizabeth Sawyer Which actor killed the man in thelma and louise? Susan Sarandon” | Narrative detail of the shooting |
| Judge | C | H | R | B |
|---|---|---|---|---|
| TruthfulQA: unsupported | ||||
| Opus-4.6 | .950 | .940 | .970 | .960 |
| GPT-4.1 | .960 | .940 | .955 | .960 |
| Gemini FL | .930 | .870 | .915 | .935 |
| Sonnet-4.6 | .950 | .890 | — | — |
| ASQA: partially supported | ||||
| Dataset | Judge | C: median [Q1, Q3] | H: median [Q1, Q3] |
|---|---|---|---|
| TruthfulQA | Opus-4.6 | 141.00 [119.00, 165.00] | 137.50 [103.75, 198.25] |
| TruthfulQA | GPT-4.1 | 106.00 [99.00, 116.00] | 104.00 [88.75, 127.00] |
| TruthfulQA | Sonnet-4.6 | 153.50 [132.00, 187.00] | 173.00 [115.00, 217.25] |
| ASQA | Opus-4.6 | 249.50 [207.00, 307.00] | 149.50 [110.00, 219.00] |
| ASQA | GPT-4.1 | 182.00 [144.00, 233.00] | 113.00 [104.00, 138.00] |
| ASQA | Sonnet-4.6 | 272.00 [224.00, 318.00] | 161.50 [132.00, 226.00] |
| Judge | Acc. | Tokens | R:H | |
|---|---|---|---|---|
| Opus-4.6 | +0.1250 | +138.39 | 50:0 | 1.78e-15 |
| GPT-4.1 | +0.2125 | +116.26 | 84:1 | 4.45e-24 |
| Gemini FL | +0.1700 | +123.23 | 69:2 | 2.17e-18 |
| Dataset | Judge | Acc. | 95% CI | Tok. | 95% CI | Stab. |
|---|---|---|---|---|---|---|
| TruthfulQA | Opus-4.6 | .0050 | [ .0150, +.0050] | +28.27 | [+25.93, +30.63] | .694 |
| TruthfulQA | GPT-4.1 | .0100 | [ .0200, .0025] | +7.92 | [+6.25, +9.52] | .952 |
| ASQA | Opus-4.6 | +.0725 | [+.0475, +.0975] | 77.11 | [ 84.29, 70.52] | 1.000 |
| ASQA | GPT-4.1 | +.1550 | [+.1200, +.1925] | 65.07 | [ 70.48, 59.84] | 1.000 |
| QAMPARI | Opus-4.6 | +.0175 | [+.0050, +.0300] | 292.79 | [ 343.09, 247.36] | .988 |
| QAMPARI | GPT-4.1 | +.0700 | [+.0475, +.0950] | 256.39 | [ 304.02, 214.09] | 1.000 |
| ASQA , num_qa_pairs (rows) | ||||
|---|---|---|---|---|
| Judge | 2 (144) | 3 (86) | 4 (94) | 5+ (76) |
| Opus-4.6 | +.076 | +.058 | +.106 | +.039 |
| GPT-4.1 | +.174 | +.233 | +.032 | +.184 |
| Gemini FL | +.181 | +.221 | +.074 | +.092 |
| QAMPARI , num_answers (rows) | ||||
| Judge | 5 (90) | 6–7 (92) | 8–9 (56) | 10+ (162) |
| Design | Rows | Whole JSON | Embedded JSON | Regex only | Canonical verdict |
|---|---|---|---|---|---|
| C | 3600 | 2765 | 833 | 2 | 3600 |
| H | 3600 | 2921 | 679 | 0 | 3600 |
| R | 3600 | 2492 | 1106 | 2 | 3600 |
| B | 3600 | 2414 | 1181 | 5 | 3600 |
| C + H | 7200 | 5686 | 1512 | 2 | 7200 |
LLM-as-a-Judge
Large language model (LLM)-as-a-judge research uses language models to score, compare, and verify AI outputs as scalable alternatives to human evaluation.
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