AI representation is emerging in digital democracy, assisting in voter emulation and decision-making. Large language models (LLMs) behave differently depending on the model, the prompt context, and the voter information they receive, representing some groups more accurately than others and potentially making the emulation unfair to certain groups. We investigate demographic biases in LLM-emulated electorates: how accurately LLMs represent individual votes, whether some voter groups are represented more accurately than others, and whether AI alignment can reduce these disparities without sacrificing overall accuracy. Using three U.S. presidential elections, we compare a closed-source and an open-source LLM across voters' demographic features and test AI alignment strategies toward fairer voter representation. Removing gender from the voter profile reduces the largest group error of the models by 22-42%, and removing education reduces it by 64%, whereas removing self-reported race increases the mean group error by over 40%, all without lowering accuracy. Common alignment strategies, such as repeated queries or fairness instructions, do not reduce these errors and can double them.
Figures & tables
Figure 1. Voter misrepresentation in AI representation. High individual accuracy (85%) and a small overall error (3 points) can coexist with a large error for one group (Group C, 14 points), reversing its ordering relative to another group.
Per-group comparison
Fairness metric
Race/ ethnicity
Multiple elections
Open & closed LLMs
Voter emulation
Argyle ( Argyle et al., 2023 )
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Bisbee ( Bisbee et al., 2024 )
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von der Heyde ( Von der Heyde et al., 2024 )
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Yu ( Yu et al., 2024 )
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Majumdar ( Majumdar et al., 2026 )
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Table 1. Comparison of closely related work across six dimensions of fairness evaluation in AI voter representation.
Dataset
Election
Vote task
N
Role
ANES 2012
Obama vs. Romney
Presidential vote
3,793
Temporal validation
ANES 2016
Clinton vs. Trump
Presidential vote
1,978
Temporal validation
ANES 2020
Biden vs. Trump
Presidential vote
5,141
Main evaluation
Table 2. Datasets used in the evaluation
Figure 2. Worst-group error over voters who self-identify with a racial or ethnic group (top) and individual accuracy (bottom) at each level of control, with one run per voter (solid) or five runs at the base level (hollow). Accuracy is stable across levels, while race-targeted control does not reduce the worst-group error: for Claude, prompt-based control raises it in every election.
Figure 3. Signed misrepresentation error (share of emulated Democratic choices minus reported share of Democratic votes) for the voter choices emulated by Claude and by Llama, by self-identified racial group, ANES 2020 (base level, K = 5; bars: 95% intervals). For both models, the share of emulated Democratic choices is furthest from the reported share for voters who self-identify as Native American (about 14 points higher) and within 1 point for voters who self-identify as Black.
Figure 4. Signed misrepresentation error (Share of emulated Democratic choices minus reported share) by group at the base level ( K=5 ), with 95% intervals; filled markers exclude zero. For voters who self-identify as male and voters with at most a high school education, the share of Democratic choices emulated by both models is below the reported share in every election, while the errors for racial groups vary across elections.
Figure 5. Gap amplification on ANES 2020 (1 = real group differences reproduced; log scale; 95% intervals). Given only the attribute, both models exaggerate group differences several-fold; the full profile still exaggerates gender and education gaps.
Worst-group error
Mean group error
1=0
1=0
Model
Left out
Full → without
Change
Full → without
Change
Acc. change
Claude
Race
.124 → .185
+49%
.043 → .061
+42%
−0.5
Gender
.107 → .062
−42%
.071 → .054
−25%
−0.3
Education
.109 → .039
−64%
.048 → .021
−57%
+0.2
Table 3. Group error when one attribute is left out of the profile (ANES 2020). Negative change = fairer.
εmax
1=0
Model
Year
Level
Acc.
Pop.
Race
Gender
Educ.
Claude
2012
Base
.822
.026
.051
.085
.048
Prompt
.825
.043 ∗
.140 ∗
.083
.091 ∗
Decomposed
.815 ∗
.050 ∗
.084
.095 ∗
.078 ∗
2016
Base
.832
.001
.071
.094
.076
Table 4. Accuracy, population-level error, and worst-group error εmax by attribute at each level of control ( K=1 , same voters). ∗ : differs from base ( p<0.05 , paired bootstrap).
Figure 6. Signed misrepresentation error by group on ANES 2020 at each level of control ( K=1 , same voters). Prompt-based control doubles Claude’s error for voters who self-identify as Native American; activation-level control shifts every Llama group toward the Democratic candidate.
Appendix figures & tables8 assets
Supplementary material from the paper’s appendix.
Appendix
Symbol
Meaning
G , r
Set of groups under one attribute; a group
Jr , Nr
Voters in group r ; their number
yj
Reported vote of voter j ( 1 = Democrat)
y^j,k
Emulated vote of voter j in run k=1,…,K
p^j
Share of runs voting Democrat, K1∑ky^j,k
y^j
Majority vote, 1[p^j>1/2]
Appendix
Table 5. Notation.
Attribute
Groups
Race
White, Black, Hispanic, Asian/NHPI, Native American, Other
Gender
Man, Woman
Age
18–34, 35–49, 50–64, 65+
Education
High school or less, Some college, Bachelor’s, Postgraduate
Appendix
Table 6. Demographic groups used in the analysis.
α
1
2
4
8
Democratic share
0.65
0.73
0.99
1.00
Appendix
Table 7. Overall Democratic share under activation-level control on 200 ANES 2020 voters (uncontrolled Llama: 0.58; reported: 0.58).
Section
Elections
Level of control
Runs
Sec.5.2 Robustness
2012, 2016, 2020
Base
K=5
Sec.5.3 Source
2020
Base, three profile variants
K=1 or 5
Sec.6.1 Aggregation
2012, 2016, 2020
Base
K=5
Sec.6.2 Control
2012, 2016, 2020
Base, prompt-based, decomposed
K=1
Sec.6.4 Prompt vs. activation
2020
Decomposed, activation (Llama)
K=1
Appendix
Table 8. Experiments. All use the voters described in Appendix B.1 .
εmax
1=0
Model
Year
K
Acc.
Race
Gender
Educ.
Claude
2012
1
.822
.051
.085
.048
3
.822
.051
.086
.048
5
.823
.051
.085
.047
2016
1
.832
.071
.094
.076
Appendix
Table 9. Accuracy and worst-group error εmax by attribute under majority voting over K runs (base level).
Method
Prompt Template
Unsteered LLM
You are simulating a survey respondent in a U.S. election study. Given the following voter profile, predict which candidate this respondent would vote for. Profile: {profile_text}. Question: Based on this profile, would this respondent vote for {Candidate A} or {Candidate B}? Answer with only one candidate name.
Naive Prompt Steering
You are simulating a survey respondent in a U.S. election study. Given the following voter profile, predict which candidate this respondent would vote for. Profile: {profile_text}. When making the prediction, consider both individual-level electoral factors such as ideology and political interest, and avoid systematically under-representing the voting preferences of the respondent’s racial or ethnic community. Question: Based on this profile, would this respondent vote for {Candidate A} or {Candidate B}? Answer with only one candidate name.
Decomposed Prompt Steering
You are simulating a survey respondent in a U.S. election study. Given the following voter profile, predict which candidate this respondent would vote for. Profile: {profile_text}. [Shared electoral reasoning block] Consider task-relevant individual-level signals, including ideology, political interest, age, education, and other non-sensitive profile attributes. [Attribute-aware representation block] Separately consider whether the prediction would systematically under-represent the voting pattern of the respondent’s racial or ethnic community. This block should be treated as an independent consideration and should not override the individual-level profile evidence. [Final prediction] Based on both blocks, would this respondent vote for {Candidate A} or {Candidate B}? Answer with only one candidate name.
Appendix
Table 10. Prompt templates for the three levels of control. Placeholders in braces are replaced with the voter’s profile and the two candidates.
Model
Year
Grouping
εmax
Worst subgroup
Signed ( n )
Sig.
Claude
2012
Race
.051
White
−.051 (2437)
2/5
Race × gender
.139
White men
−.139 (1205)
3/9
Race × age
.118
Other, 35–49
−.118 (34)
3/14
Race × education
.149
Hispanic, Bachelor’s
+.149 (87)
3/14
2016
Race
.071
Asian/NHPI
+.071 (42)
0/5
Race × gender
.175
Hispanic men
−.175 (80)
4/8
Appendix
Table 11. Worst-group error εmax for race and its intersections (base level, K=5 ). “Worst subgroup” gives the subgroup with the largest error, its signed error (positive: share of emulated Democratic choices above the reported share), and its size. “Sig.” counts subgroups whose 95% interval excludes zero, out of all subgroups with at least 30 respondents.
Model
Left out
Metric
Full
Without
Difference [95% CI]
Change
p
Claude
Race
Worst-group error
.124
.185
+.061 [ −.050 , +.153 ]
+49%
.294
Mean group error
.043
.061
+.018 [ +.004 , +.043 ]
+42%
.008
Accuracy
.847
.842
−.005 [ −.011 , .000 ]
.086
Gender
Worst-group error
.107
.062
−.045 [ −.054 , −.036 ]
−42%
<.001
Mean group error
.071
.054
−.018 [ −.031 , −.004 ]
−25%
.020
Accuracy
.847
.844
−.004 [ −.011 , +.003 ]
.328
Appendix
Table 12. Change when one attribute is left out of the voter profile (ANES 2020). Differences are “without” minus “full”; negative error differences mean fairer representation. Bold: p<0.05 .
Demographic bias in language models studies how identity cues shape model outputs, decisions, and representations, and how to detect and reduce resulting disparities.
Institute of Computer Science, Czech Academy of Sciences, Prague, Czech Republic. · Faculty of Arts, Charles University, Prague, Czech Republic. · distil labs, Berlin, Germany.