The Personality Consortium is a large-scale collaborative effort to conduct a genome-wide association meta-analysis on all GWAS datasets with personality data. A challenge is that a variety of instruments have been used to assess multiple aspects of personality and also that the same construct, e.g. Neuroticism, has been assessed with different instruments. These instruments include Costa and McCrae's revised NEO Personality Inventory, Eysenck's Personality Questionnaire, Cloninger's Temperament and Character Inventory, the Amsterdamse Biografische Vragenlijst, the Minnesota Multiphasic Personality Inventory, the International Personality Item Pool and others.

We propose to use Item Response Theory (IRT) analysis to map the personality data from the different questionnaires to the same constructs. The advantages of this approach include increased statistical power because of increased sample size and enhanced precision in measuring personality traits by taking a latent variable approach. Currently, several cohorts, with a total sample size of ~150,000 subjects (of which ~60.000 have GWAS data), have expressed an interest in taking part and sharing data.