Large language models (LLMs) demonstrate impressive performance across a wide range of general NLP tasks; however, their effectiveness in sensitive domains, such as hate speech detection, remains less clear. Prior studies comparing prompted LLMs with state-of-the-art encoder-based models (e.g., BERT variants (Roy et al., 2023; Dönmez et al., 2024)) have shown only marginal gains, suggesting that LLMs may not excel in hate speech detection or mitigation. In this work, we revisit this question through the lens of instruction tuning. By thoroughly unifying 36 English hate speech datasets spanning multiple labeling schemes, we fine-tune a generalist LLM, based on Qwen3 (Qwen Team, 2025), specifically for hate speech mitigation. Our results demonstrate not only state-of-the-art performance on in-domain benchmarks but also substantial improvements in cross-domain and cross-lingual generalization--areas where encoder-based specialist classifiers often struggle.
Figures & tables
Figure 1: In this work, we would like to close the gap in understanding if instruction-tuned general-purpose LLMs (i.e., HIPPO, right) are more robust and precise detectors of hate speech than specially-tuned LMs (i.e., BERT and Llama, left).
Dataset
Attribution
Train
Test
Domain
Label Type
(Sub)Tasks
CAD
Vidgen et al. (2021)
13423
Multilabel
1
CAT-LARGE
Pavlopoulos et al. (2020)
19870
Binary
1
CONAN
Chung et al. (2019)
408
Synthetic
Generation
1
ConvAbuse
Cercas Curry et al. (2021)
4013
Chatbot
Hierarchical
4
DialoCONAN
Bonaldi et al. (2022)
1299
Synthetic
Generation
1
EAP
Vidgen et al. (2020)
19989
Multiclass
1
Table 1: List of datasets used and the number of examples, domain, and type of labels. Domains include Twitter ( ), Reddit ( ), Gab ( ), Facebook ( ), Wikipedia ( ), YouTube ( ), and Civil Comments (CC), among others.
Dataset
Type
HIPPO
Indiv.
GPT5
Best
Best Arch.
Best Source
AMI18 - A
Binary
81.0
74.8
70.9
71.0
BERT
Muti and Barrón-Cedeño (2022)
AMI18 - B
Binary x2
73.4
64.3
44.4
42.9
BERT
Pamungkas et al. (2020b)
EDOS - A
Binary
83.7
85.0
73.0
88.4
PaLM
Sorensen et al. (2023)
EDOS - B
Multiclass
71.2
65.5
41.9
73.3
PaLM
Sorensen et al. (2023)
EDOS - C
Multiclass
51.8
47.5
41.0
56.1
DeBERTa-v3
Zhou (2023)
HASOC19 - A
Binary
76.7
79.0
72.7
79.5
RoBERTa †
Kovács et al. (2021)
Table 2: Comparison of our unified model ( HIPPO , based on Qwen3-4B-Instruct-2507 ) to individually trained models (Indiv.), GPT5-mini, and to the best performing models in literature. Bold values denote the best results per dataset. † denotes ensembles.
Dataset
0.6B
4B
32B
Best
AMI18 - A
28.1
81.0
82.9
71.0
AMI18 - B
26.0
73.4
75.5
42.9
EDOS - A
23.5
83.7
87.0
88.4
EDOS - B
42.0
71.2
74.7
73.3
EDOS - C
27.5
51.8
57.9
56.1
HASOC19 - A
22.2
76.7
76.6
79.5
Table 3: Effectiveness of instruction tuning on varying model sizes, compared to the SOTA. Blue values indicate scores that outperform the SOTA. Bold values denote the best results per dataset.
Dataset
Zero-shot
LOO
Full
AMI18 - A
59.8
78.4
81.0
AMI18 - B †
41.6
42.1
73.4
EDOS - A
66.7
76.0
83.7
EDOS - B ‡
37.9
43.4
71.2
EDOS - C ‡
20.2
27.6
51.8
HASOC19 - A
71.5
70.3
76.7
Table 4: Comparison of zero-shot to leave-one-out (LOO) and full HIPPO (i.e., unified) training. ‡ denotes tasks that do not have equivalent tasks in training of Qwen3-4B . † denotes partial equivalence: AMI18-B and HatEval19-B are composed of 2 tasks, both of which include 1 task that has no similar task in training. Blue values indicate scores that outperform the zero-shot baseline. Bold values denote the best results per dataset.
Figure 2: Cross-lingual and functional performance of the zero-shot, minimally-trained, and fully-trained HIPPO . Note: Unlike for English, HASOC19 does not have a Task C for German and Hindi.
Figure 3: Performance of the fully-trained HIPPO on all languages (ordered by performance) of HateCheck, per functional task. Above the black line are hateful functionalities, below are non-hateful. Only functionalities shared across all languages are shown.
Appendix figures & tables9 assets
Supplementary material from the paper’s appendix.
Appendix
Parameter
Value
Batch size
64
Learning rate
1e-4
Weight decay
1e-3
Warmup ratio
1e-2
Epochs
3
LoRA rank
32
Appendix
Table 5: Hyperparameters used in training.
Figure 4: Top-level label distribution of all datasets.
Figure 5: Fine-grained label distribution of the hierarchical datasets.
Resource
License
Homepage
CAD
CC BY 4.0
https://github.com/dongpng/cad_naacl2021
CAT-LARGE
Apache-2.0
https://github.com/ipavlopoulos/context_toxicity
CONAN
Research Only
https://github.com/marcoguerini/CONAN
ConvAbuse
CC BY 4.0
https://github.com/amandacurry/convabuse
DialoCONAN
Research Only
https://github.com/marcoguerini/CONAN
EAP
CC BY 4.0
https://zenodo.org/records/3816667
Appendix
Table 6: Overview of the licenses associated with each resource utilized in this work for experiments.
Dataset
Examples
Label
AMI18 Subtask 1
There are some wins that will make u go hysterical. Some makes you happy but same time you are sad
Non-misogyny
Shut the fck up you fcking monkey jew btch cnt ngger dck l*cking
Misogyny
he thing is if a woman speaks out about rape on Nigerian twitter.The backlash would be shocking. It’s not good for the mind. Hence silence
Non-misogyny
EDOS Subtask 2
MRA stuff like men saying they wished they hadn’t had daughters, calling ALL American women wh*res, etc. Evidence if this?
Threats
Is this ASD (anti sl*t defence) or what? How do I prevent this? Spend more time with her before and after.
Derogation
Not our fault she chose to date an abusive sc*mbag.
Animosity
Appendix
Table 7: Examples from a few classification datasets used in our work for experiments. We included multiple subtasks and domains, covering just high-level classification of hate/non-hate as well as other more fine-grained labels.
Dataset
Examples
ToxicSpans
Input Text : your an idot, this is a tax based on a lie Toxic Span : idot
Input Text : Have you walked around Denver lately , or Civic Center Park ? These poor homeless people are pgs ! Toxic Span : pgs
Input Text : Mron. Illegals have no Constitutional rights Toxic Span : Mron
ParaDetox
Input Text : the police dont have time for this cr*p. Detoxified : The police have no time for this.
Input Text : its a crock of sh*t , and you know it . Detoxified : It’s senseless, you know
Input Text : i didnt vote for the liar Detoxified : I didn’t vote for him
Appendix
Table 8: Examples from a few generation datasets used in our work for experiments. We included not only classification, but generation tasks showing that instruction-tuned model can be used for more variety of proactive ways for hate speech mitigation.
Dataset
Llama3.2
Phi4-mini
Qwen3
HIPPO
AMI18 - A
78.7
75.7
79.2
81.0
AMI18 - B
70.3
54.8
72.5
73.4
EDOS - A
83.5
83.5
84.6
83.7
EDOS - B
70.0
61.9
67.5
71.2
EDOS - C
43.8
41.4
47.5
51.8
HASOC19 - A
77.6
74.5
78.1
76.7
Appendix
Table 9: Comparison of model types. We can observe that Qwen3 family models ( Qwen3 and HIPPO ) perform better and more stable in comparison to other same-sized models from other families.
Figure 6: Confusion matrices for all classification-based tasks in the test set. Predicted label categories correspond to the true label categories, abbreviated for brevity.
Figure 7: Difference of confusion matrices between the unified model and individual models. Blue indicates better performance for unified, red vice versa.
Department of Computer Sciences Information Technology University Lahore (54000), Pakistan · Artificial Intelligence Technology Centre National Centre for Physics Islamabad (44000), Pakistan