Key opinion leader (KOL) programs enlist influencers to build awareness and drive marketing’s impact among medical and scientific professionals. Although KOL programs must adhere to compliance requirements, measurement plans should match organizational goals with success metrics. In an era of decreasing access to medical professionals and dwindling sales forces, it’s essential to verify that these core influencer programs are driving the anticipated benefits. In this report, we describe how senior organizational leaders can use the Forrester Metrics Spectrum to measure the success of a KOL program by using four types of metrics.