The number of programs dedicated to countering violent extremism (CVE) has grown in recent years, yet a fundamental gap remains in the understanding of the effectiveness of such programs. This is particularly the case for CVE campaigns, which are increasingly conducted in the online space. The goal of this report is to help CVE campaign planners better evaluate the impact of online efforts. It reviews prior assessments of online CVE campaigns, provides recommendations for future assessments, and provides a case study of one particular CVE campaign — the Redirect Method. A limited evaluation of the Redirect Method process variables suggests that the implementers are able to use advertisements linking to counterextremist videos to effectively expose individuals searching for violent jihadist or violent far-right content to content that offers alternative narratives. Users clicked on these ads at a rate on par with industry standards. However, as is the case with other CVE evaluations, this partial evaluation did not assess the impact of the video content on user attitudes or behavior. The potentially highly radical nature of the Redirect Method’s target audience makes evaluation of the campaign particularly complicated and therefore might necessitate the recruitment of former extremists to help gauge audience response. Alternatively, it might be advisable to analyze user comments to understand how a subsample of users respond to the content.