This study examined for Neuroticism and Extraversion personality traits whether measures from different inventories could be harmonized using IRT test linking. The IRT analyses showed that the linked scores for Neuroticism and Extraversion that were estimated in >160,000 individuals from 23 cohorts were largely independent of the particular inventory. The success of this approach is demonstrated by the power study that showed a clear increase in statistical power to find a genetic variant associated with personality that is mainly the result of an increase in sample size.
