Complex claim verification requires decomposing sentences into verifiable subclaims, yet existing methods struggle to align decomposition quality with verification performance. We propose a reinforcement learning (RL) approach that jointly optimizes decomposition quality and verifier alignment using Group Relative Policy Optimization (GRPO). Our method integrates: (i) structured sequential reasoning; (ii) supervised finetuning on teacher-distilled exemplars; and (iii) a multi-objective reward balancing format compliance, verifier alignment, and decomposition quality. Across six evaluation settings, our trained 8B decomposer improves downstream verification performance to (71.75%) macro-F1, outperforming prompt-based approaches ((+1.99), (+6.24)) and existing RL methods ((+5.84)). Human evaluation confirms the high quality of the generated subclaims. Our framework enables smaller language models to achieve state-of-the-art claim verification by jointly optimising for verification accuracy and decomposition quality.
Figures & tables
Figure 1: Distill-Align-Decompose (DAD). We (1) distill examples from a teacher model, (2) frame decomposition as a sequential reasoning task, and (3) align the policy via GRPO using multi-objective rewards.
Decomposer
Approach
PerplexityAI
ChatGPT
FELM
BINGCHAT
Overall
Atomicity-1
Atomicity-2
Atomicity-1
Atomicity-2
BAcc
F1
SC
BAcc
F1
SC
BAcc
F1
SC
BAcc
F1
SC
BAcc
F1
SC
BAcc
F1
SC
BAcc
F1
SC
Baselines
Llama-3.1-8B
FActScore
76.10
65.72
10.76
71.40
67.07
16.66
72.60
73.68
11.08
61.60
64.33
17.55
53.93 *
64.04 *
8.9 *
50.24 *
58.24 *
72.56 *
64.31
65.51
22.92
Mistral-7B
VeriScore-SFT
73.50
65.61
2.50
66.60
63.63
4.46
77.40
77.69
2.68
76.90
75.79
4.90
52.59
66.40
4.39
51.51
64.23
21.26
66.42
68.89
6.70
Llama-3.1-8B
VeriScore
78.60
71.61
2.49
71.00
68.48
4.20
82.30
82.76
2.85
73.70
75.84
5.76
59.56 *
67.86 *
6.65 *
52.15 *
52.02 *
28.00 *
69.55
69.76
8.33
Table 1: Balanced Accuracy (BAcc), macro-F1, and subclaim count (SC) per dataset. Best BAcc and F1 in each column are bold . The final block reports overall BAcc/F1 and the average SC. Entries marked * are reported from Hu et al. (2025) under a similar setup. On average across six evaluation settings, our 8B decomposer leads to the highest verification performance, with BAcc 71.37% and macro-F1 71.75% , while maintaining comparable granularity (avg. 8.14 subclaims).
Dataset
Metric
DAD ClearCheck
Llama-8B ClearCheck
PerplexityAI Atom.-1
BAcc
72.50
69.50
MacroF1
67.00
66.50
PerplexityAI Atom.-2
BAcc
71.70
59.70
MacroF1
70.80
59.80
ChatGPT Atom.-1
BAcc
79.60
66.60
MacroF1
79.90
65.40
Table 2: DAD vs. Llama-8B decomposers paired with a non-aligned ClearCheck-8B verifier. DAD consistently outperforms Llama-8B, demonstrating that the decomposer provides value even without verifier-specific alignment . Bold indicates the higher score per dataset and metric.
Training Configuration
PerplexityAI
FELM
F1
SC
F1
SC
Prompt only (no training)
67.46
2.00
68.57
5.05
RL only (no SFT)
+ Format + Verifier Accuracy (sparse)
70.86
1.95
58.94
3.78
+ Format + Verifier Brier (dense)
72.71
1.49
64.94
3.40
SFT only
71.55
2.28
66.39
5.01
Table 3: Ablation study on different training setups. We report macro-F1 and Average Subclaim Count (Avg. SC) on PerplexityAI and FELM , plus overall F1. Best F1 per column is bold .
Figure 2: Verifier training rewards (dense vs. sparse). Training the base policy with the verifier Brier reward ( ∙ dense) yields smoother, more sample-efficient learning than the sparse accuracy reward ( ∙ sparse).
Figure 3: Human-evaluated subclaim decomposition quality across the five desiderata. Our method achieves comparable completeness to baselines while maintaining high scores across other desiderata. Scores represent sentence-level averages of subclaim quality with higher values indicating better quality for a given desideratum.
Appendix figures & tables8 assets
Supplementary material from the paper’s appendix.
Appendix
Granularity
Dataset
Atomicity
Size
KS
Sentence
PerplexityAI
1
300
Wiki
ChatGPT
1
249
Wiki
PerplexityAI
2
149
Wiki
ChatGPT
2
115
Wiki
Response
FELM
—
184
Google
BINGCHAT
—
396
Google
Appendix
Table 4: Evaluation datasets by label granularity, atomicity, and size. Abbreviations: KS = Knowledge Source; Wiki = Wikipedia.
Desiderata
3-way (%)
Fleiss’ κ
Pairwise (%)
κ
r
Completeness
80.8
0.5
A1-A3: 85.0
0.5
0.5
A1-A2: 85.9
0.5
0.5
A3-A2: 90.9
0.6
0.6
Uniqueness
92.9
0.9
A1-A3: 94.0
0.8
0.8
A1-A2: 93.9
0.8
0.8
A3-A2: 97.0
0.9
0.9
Appendix
Table 5: Inter-annotator agreement statistics across the five desiderata. 3-way agreement shows percentage agreement among all three annotators (A1, A2, A3) with Fleiss’ κ for multi-annotator reliability. Pairwise statistics include percentage agreement, Cohen’s κ , and Pearson correlation coefficient (r) for each annotator pair.
Question
Businessman, a Jewish American, grew up and lived in New York City, associated with the Democratic Party, and eventually became very famous. His name is "Bernie"-what?
Sentence
Bernie Sanders.
Subclaims
Bernie Sanders
Human Annotation Scores
Completeness Redundancy Verifiability Coherence Clarity Majority Majority Average Average Average 0 1 0 1 0
Question
Tell me a bio of Paul Kruger.
Sentence
Kruger was a prominent figure in the Boer War (1899-1902), leading the Boers in their defense against the British Empire. Kruger was a staunch believer in Boer independence and was instrumental in securing the Transvaal’s independence from British rule in 1881.
Appendix
Table 6: Subclaims and Human Annotation Scores for Example Questions
Method
What is Similar to Our Approach
What is Different / Missing Compared to Ours
FActScore Min et al. (2023)
Focuses on atomic fact extraction; uses selection and extraction steps.
Over-decomposes (too many subclaims); does not optimize for verifier alignment; lacks explicit decontextualization and relationship identification.
VeriScore Song et al. (2024)
Emphasizes verifiability in claim extraction; uses prompt-based decomposition.
Does not explicitly decontextualize claims; lacks relationship identification; does not jointly optimize decomposition and verifier alignment.
Focuses only on decontextualization; does not address selection, relationship identification, or verifier alignment.
Claimify Metropolitansky and Larson (2025)
Separates selection, disambiguation, and extraction into distinct steps.
Uses complex, multi-stage process with closed-source models; does not jointly optimize decomposition and verifier alignment; lacks efficiency of single model call.
DyDecomp Lu et al. (2025)
RL-based optimization for when to decompose, using verifier feedback.
Only decides when to decompose, not how; does not improve decomposition quality or address relationships and decontextualization.
DndScore Wanner et al. (2024b)
Focuses on decontextualization and decomposition for factuality verification.
Does not integrate selection, relationship identification, and verifier alignment in a unified framework.
Appendix
Table 7: Comparison of Decomposer-Focused Methods: Similarities and Differences with Our Approach
Field
Content
Example 1: Frederick Howard Taylor
Question
Tell me a bio of Frederick Howard Taylor.
Original Claim
Howard Taylor attended the Royal College of Surgeons where he received three high honors in his postgraduate studies.
Subclaims
1. Howard Taylor attended the Royal College of Surgeons where he received three high honors in his postgraduate studies.
Ground Truth Label
Not Supported (NS)
Model Prediction
Supported (S)
Appendix
Table 8: Detailed Verification Error Analysis with Subclaims and Evidence
Field
Content
Example 1: Lina Medina [Dataset: ChatGPT, Atomicity 1]
Question
Tell me a bio of Lina Medina.
Original Claim
Lina lived a relatively private life after the birth of her son and later married in 1970, but little else is known about her current whereabouts or status.
Reasoning
STEP 1: The target sentence contains verifiable claims about Lina Medina’s life after the birth of her son, specifically that she lived a relatively private life and later married in 1970. However, the sentence also mentions that little else is known about her current whereabouts or status, which is a lack-of-information statement and should be excluded . The verifiable sentence is: "Lina lived a relatively private life after the birth of her son and later married in 1970." STEP 2: To decontextualize the sentence, we need to ensure it is clear, self-contained, and contextually relevant. The sentence already mentions Lina’s name, and the context provides the necessary information about her son’s birth. The decontextualized sentence is: "Lina Medina lived a relatively private life after the birth of her son and later married in 1970." STEP 3: Analyzing the decontextualized sentence, we can identify the following relationships: - Temporal relationship: Lina lived a private life after the birth of her son and later married in 1970 (time sequence). - Expansion relationship: The sentence provides additional information about Lina’s life after the birth of her son (elaboration). STEP 4: To split the claim into the smallest possible factual units, we can break it down into two separate claims: - Claim 1: Lina Medina lived a relatively private life after the birth of her son. - Claim 2: Lina Medina married in 1970.
Subclaims
1. Lina Medina lived a relatively private life after the birth of her son. 2. Lina Medina married in 1970.
Model prediction
Not Supported (NS)
Appendix
Table 9: Decomposition analysis with reasoning traces. Highlighted segments are discussed in Appendix F .
Field
Content
Example: Harrison Ford
Question
Tell me a bio of Harrison Ford.
Text
He was born on July 13, 1942, in Chicago, Illinois, to former radio actress Dorothy and advertising executive John William "Christopher" Ford.
Label
Supported
FactScore (FS) Subclaims
[ ‘ He was born on July 13, 1942.’, ‘ He was born in 1942.’, ‘1942 is a year.’ , ‘July 13 is a date.’ , ‘July 13 is a date in 1942.’ , ‘He was born on July 13.’, ‘He was born in July 1942.’, ‘July is a month.’ , ‘July is a month of 1942.’, ‘He was born in July.’, ‘He was born in July 1942.’, ‘He was born in 1942.’, <.. repeated variants of ‘He was born in the year of his birth, 1942.’ ..> ]
Prediction using FS subclaims
Not Supported
Appendix
Table 10: Examples comparing decompositions across several methods. Highlighted issues with decompositions.
Field
Content
Example: Scientist (musician)
Question
Tell me a bio of Scientist (musician).
Text
He was a protégé of King Tubby and worked alongside other pioneers of the genre such as Bunny Lee, Philip Smart, Pat Kelly, and Prince Jammy.
Label
Supported
FactScore (FS) Subclaims
[ ‘ He was a protégé of King Tubby.’, ‘King Tubby is a person.’ , ‘ He was a protégé.’, ‘ He was a protégé of King Tubby.’, ‘King Tubby is a person who was a mentor.’, ‘He worked alongside other pioneers of the genre.’, ‘The genre is a type of music.’ , ‘Bunny Lee is a pioneer of the genre.’, ‘He worked alongside Bunny Lee.’, ‘Philip Smart is a pioneer of the genre.’, ‘He worked alongside Philip Smart.’, ‘Pat Kelly is a pioneer of the genre.’, ‘He worked alongside Pat Kelly.’, ‘Prince Jammy is a pioneer of the genre.’, ‘He worked alongside Prince Jammy.’ ]
Prediction using FS subclaims
Not Supported
Appendix
Table 11: Examples comparing decompositions across several methods. Highlighted issues with decompositions. (continued)
Claim verification splits between end-to-end classifiers that are accurate but yields no inspectable traces, and decomposition-based methods produce inspectable traces but lag performance on benchmark datasets. We propose DecomposeRL an accurate claim-verifier that produce inspectable traces. DecomposeRL frames decomposition as an RL policy trained with GRPO and a multi-faceted reward ensemble, enabling both fully supervised and semi-supervised learning from unlabeled claims. DecomposeRL addresses the prohibitive training cost of GRPO with a data-curation funnel that distills 115K fact-verification claims into a compact, learning-signal-dense subset of 5K claims. We show that a DecomposeRL-7B policy trained with full supervision on only ~5K curated claims achieves 86.3 in-domain and 69.8 out-of-domain balanced accuracy across 11 claim-verification benchmarks containing biomedical, political, scientific, and general-domain claims. Despite being 4x smaller, it matches 32B baselines and GPT-4.1-mini, and it further outperforms baselines in a semi-supervised setting with only 10% labeled claims data. Code, data, and models are available at https://dipta007.github.io/DecomposeRL
Shubhashis Roy Dipta, Ankur Padia, Francis Ferraro
Department of Computer Science and Electrical Engineering · University of Maryland Baltimore County · Baltimore, MD 21250 USA
We present ThinknCheck, a 1B-parameter verifier for grounded claim verification that first produces a short, structured rationale and then a binary verdict. We construct LLMAggreFact-Think, a 24.1k reasoning-augmented training set derived from LLMAggreFact, and fine-tune a 4-bit Gemma3 model to follow this format. On LLMAggreFact, ThinknCheck attains 78.1 balanced accuracy (BAcc), surpassing MiniCheck-7B (77.4) with 7x fewer parameters; removing the reasoning step reduces BAcc to 57.5. On SciFact, ThinknCheck reaches 64.7 BAcc, a +14.7 absolute gain over MiniCheck-7B. By contrast, zero-shot chain-of-thought on the base Gemma3-1B harms accuracy relative to direct answers, and preference optimization with a simple format+accuracy reward underperforms supervised reasoning. To probe the latter, we introduce GSMClaims and a domain-specialized variant, ThinknCheck-Science, which improves across benchmarks, including 61.0% accuracy on GSMClaims. Overall, explicit, supervised reasoning enables compact verifiers that are competitive while remaining resource-efficient and interpretable.
We present a novel approach for claim verification from tabular data documents. Recent LLM-based approaches either employ complex pretraining/fine-tuning or decompose verification into subtasks, often lacking comprehensive explanations and generalizability. To address these limitations, we propose a Multi-Agentic framework for Claim verification (MACE) consisting of three specialized agents: Planner, Executor, and Verifier. Instead of elaborate finetuning, each agent employs a zero-shot Chain-of-Thought setup to perform its tasks. MACE produces interpretable verification traces, with the Planner generating explicit reasoning strategies, the Executor providing detailed computation steps, and the Verifier validating the logic. Experiments demonstrate that MACE achieves state-of-the-art (SOTA) performance on two datasets and performs on par with the best models on two others, while achieving 80--100% of best performance with substantially smaller models: 27--92B parameters versus 235B. This combination of competitive performance, memory efficiency, and transparent reasoning highlights our framework's effectiveness.
Rudra Ranajee Saha, Laks V. S. Lakshmanan, Raymond T. Ng