This document discusses research from CEB on how to improve sales performance in complex sales environments. It found that sales reps with a "Challenger" approach, who challenge customers' assumptions and take control of conversations, are most likely to be high performers. These Challenger reps use disruptive insights to push customers' thinking and lead them back to the seller's strengths. The document also outlines CEB's services to help companies develop Challenger reps, including training, content development, and implementation support.