Large language models (LLMs) are increasingly evaluated for fairness, yet most existing benchmarks audit one sensitive attribute at a time. This single-attribute paradigm can miss intersectional harms, where multiple attributes interact non-additively and produce failures that are invisible under marginal evaluation. We introduce ComFair, a configurable benchmark that converts existing fairness data into 479,066 controlled Dual- and Multi-attribute instances and pairs every augmented instance with its task-equivalent source. Across Recognition, Selection, Continuation, and Conversation, this pairing supports a unified audit of performance or bias-score shifts, how often added attributes introduce new errors or mask existing ones, and model-ranking stability. Experiments on ten LLMs show task- and subgroup-dependent sensitivity: discriminative tasks expose both transition directions even when aggregate changes are modest, generative tasks exhibit larger and directionally asymmetric shifts, and rankings vary with attribute composition. ComFair therefore provides a scalable controlled sensitivity audit---rather than a model of the natural joint distribution of identities---for testing the robustness of fairness-benchmark conclusions beyond single-attribute settings.
Figures & tables
Figure 1: Overview of single-attribute and intersectional fairness auditing.
Benchmark
#Inst.
Task Coverage
Sensitive-Attribute Support
Cont.
Conv.
Sel.
Rec.
Single
Dual
Multi
BBQ Parrish et al. (2022)
58,492
–
–
✓
–
✓
✓
–
CrowS-Pairs Nangia et al. (2020)
1,508
–
–
✓
–
✓
✓
–
StereoSet Nadeem et al. (2021)
16,995
✓
–
✓
–
✓
–
–
WinoGender Rudinger et al. (2018)
720
–
–
✓
–
✓
–
–
WinoBias Zhao et al. (2018)
3,160
–
–
✓
–
✓
–
–
Table 1: Coverage of representative LLM fairness benchmarks. Our benchmark unifies fairness evaluation across four task types( Continuation, Conversation, Selection, Recognition ) and supports single , dual , multi-way sensitive-attribute assessment.
Figure 2: ComFair’s task-preserving pipeline for constructing intersectional evaluation pairs.
Task
Single
Dual
Multi
Aug. total
Recognition
11,745
89,571
156,479
246,050
Selection
6,272
43,173
75,829
119,002
Continuation
2,368
14,812
24,983
39,795
Conversation
2,378
15,867
58,352
74,219
Table 2: ComFair instances by task and composition depth; Aug. total = Dual + Multi.
Model
Gender
Race
Base
+White ( Δ )
+Black ( Δ )
Base
+Male ( Δ )
+Female ( Δ )
DS-V3.2-C
31.42
40.69 (+9.27)
35.00 (+3.58)
38.90
39.79 (+0.89)
40.71 (+1.81)
DS-V3.2-R
33.13
36.54 (+3.41)
32.25 (-0.88)
36.53
46.65 (+10.12)
40.71 (+4.18)
Gem-3F
28.99
30.69 (+1.70)
23.41 (-5.58)
40.59
41.67 (+1.08)
43.14 (+2.55)
GPT-5-mini
26.12
34.15 (+8.03)
27.75 (+1.63)
34.22
38.33 (+4.11)
36.86 (+2.64)
Qwen3-8B
33.73
41.23 (+7.50)
37.03 (+3.30)
40.00
45.88 (+5.88)
43.86 (+3.86)
Table 5: Human continuation bias scores for the same paired interventions as Table 4 . Lower is fairer.
Model
+White
+Black
+Male
+Female
DS-V3.2-C
+4.54
-2.69
-3.59
-3.02
DS-V3.2-R
+6.61
-1.22
+13.32
+3.52
Gem-3F
+2.47
-8.19
+7.06
+1.95
GPT-5-mini
+3.38
-1.08
+0.61
-0.28
Qwen3-8B
+4.21
-1.46
+2.67
+3.02
Qwen3-235B
+8.70
-6.52
+0.61
-3.41
Table 6: Representative Continuation bias-score Δ values after re-scoring Table 4 outputs with DeepSeek-V4-Pro.
Model
+White
+Black
+Standing
White − Standing
Black − Standing
DS-V3.2-C
+0.0647
+0.1741
-0.0197
+0.0844
+0.1938
DS-V3.2-R
+0.0344
+0.1184
-0.0059
+0.0403
+0.1243
GPT-5-mini
+0.0159
+0.2012
-0.0362
+0.0521
+0.2374
Qwen3-235B
+0.0109
+0.0155
+0.0218
-0.0109
-0.0063
Qwen3-8B
-0.0023
+0.0006
+0.0007
-0.0030
-0.0001
Mean
+0.0247
+0.1020
-0.0079
+0.0326
+0.1098
Table 7: Selection matched-placebo F1 shifts. The last two columns subtract the non-demographic “standing” shift from each demographic shift.
Model
Gender
Race
+Black
+White
+Female
+Male
Agg.
Mask.
Agg.
Mask.
Agg.
Mask.
Agg.
Mask.
Claude-3.5
33.59%
43.66%
43.61%
14.83%
18.97%
29.70%
22.68%
28.00%
Claude-3.7
33.33%
46.60%
51.72%
20.30%
17.13%
28.48%
23.56%
29.19%
DS-V3.2-C
0.00%
20.97%
0.00%
24.62%
0.00%
10.53%
0.00%
5.13%
DS-V3.2-R
31.78%
48.76%
19.84%
32.26%
9.16%
22.69%
13.28%
20.49%
Table 8: Recognition aggravation (Agg.) and masking (Mask.) rates under paired Gender ↔ Race interventions.
Figure 3: Model-ranking stability under intersectional augmentation, measured by Spearman’s rank correlation coefficient (SRCC).
Figure 4: Aggravation case (Correct → Wrong).
Figure 5: Masking case (Wrong → Correct).
Appendix figures & tables5 assets
Supplementary material from the paper’s appendix.
Appendix
Task
Dataset
Base attribute Abase
Added attribute set Aadd
Added values / schema
#Aug / sample
Size (Orig → Aug)
Single / Dual / Multi
Recognition
BBQ WinoBias CrowS-Pairs
Age Gender RaceEthnicity PhysicalAppearance Nationality SES DisabilityStatus Religion SexualOrientation