By model size: Across different model sizes of the same training configuration (i.e.,
Flan-PaLM 8B, Flan-PaLM 62B, and Flan-PaLM 540B), the reliability of simulated per-
sonality increased with model size. Across model sizes of Flan-PaLM, as shown in Table
7, internal consistency reliability (i.e., α) of IPIP-NEO scores improved from acceptable to
excellent. At 8B parameters, internal consistency was acceptable for IPIP-NEO Openness
(α = 0.75), good for IPIP-NEO Extraversion and Agreeableness (αs 0.83, .88, respectively),
and excellent (α ≥ 0.90) for IPIP-NEO Conscientiousness and Neuroticism. At 62B parame-
ters, internal consistency was good for IPIP-NEO Openness (α = 0.84) and excellent for all
other traits (α ≥ 0.90). At 540B parameters, all IPIP-NEO domain scales showed excellent
internal consistency (α ≥ 0.90). Our other reliability indices, Guttman’s λ6 and McDonald’s
ω, improved within the same excellent range from 8B to 540B variants of Flan-PaLM.

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PersonalityTraitsinLargeLanguageModels