This validation study examines whether personality-based fit models can reliably predict employee performance and retention over time. Drawing on 18 months of real hiring data from a financial services company, it tests two models — Role Fit and Culture Fit — against actual outcomes, including sales performance ratings, tenure length, and attrition risk. The study also checks whether the same personality patterns that defined success in 2024 continued to hold in 2025.

Main findings:

• High-fit employees stayed ~16 months longer than low-fit peers, with consistent results across both 2024 and 2025 data.
• Fit scores positively predicted sales performance.
• Models grew more stable over time, converging on a clearer success profile.
• An "agreeableness paradox" emerged — agreeable employees stay longer, but top sales performers tend to be more assertive, meaning retention and performance fit may require different profiles.