This document is a technical report detailing the Thomas Personality assessment, which utilizes the High Potential Trait Indicator (HPTI) to evaluate personality in a workplace context. Developed by Ian MacRae and Adrian Furnham in 2006, the assessment is based on the Big 5 personality theory and measures six traits: Conscientiousness, Adjustment, Curiosity, Risk Approach, Ambiguity Acceptance, and Competitiveness. The assessment comprises 78 items rated on a 1-7 Likert scale and is available online in multiple languages. It aims to predict workplace performance and potential by distinguishing stable personality traits from teachable skills. The report also discusses the criterion-related validity of the HPTI, referencing a peer-reviewed study that correlates HPTI traits with subjective success metrics in the workplace, indicating that Conscientiousness is the strongest predictor of success. The findings are supported by data from various studies conducted across multiple countries.