Six Sigma is a data-driven, scientific approach to process improvement that can be applied to recruitment. It involves defining problems, measuring key metrics, analyzing causes of defects, improving the process, and controlling improvements. When applied to recruitment at Matrix, Six Sigma helped properly understand hiring needs, identify the best recruitment approach, select effective messaging and media, improve shortlisting and onboarding, and control costs. It created a better, continuously improving process that attracted more top talent.