It's superstition. The entire interview process is, to be honest. Whenever anyone studies how potential candidates are rated, compared to how they actually end

It's superstition. The entire interview process is, to be honest. Whenever anyone studies how potential candidates are rated, compared to how they actually end up performing on the job, it turns out there are two things that have significant predictive power: an IQ test (illegal in some jurisdictions), and a test of skills that will be required on the job (e.g. for a programmer, asking the candidate to write some code). Nothing else has predictive power significantly better than random chance. You might as well choose candidates based on their star sign.