A rapidly growing company relies on its hiring manager's 'gut feeling' to select new employees. The manager conducts free-flowing, conversational interviews, asking different questions to each candidate based on how the conversation evolves. Recently, the company has noticed that many of their new hires are not performing as well as expected. Based on this information, evaluate the company's interview process. What is the most likely reason for their recent hiring struggles, and what specific change would most improve their ability to predict a candidate's future job performance?