Terrorist groups do not operate in isolation. To survive in the face of counter-pressures from their opponents, the group must establish a beneficial relationship with a targeted audience, a presumed constituency, in order to generate the sympathy and support necessary for maintaining operational viability. Existing studies of terrorism, however, offer few insights into how this might be done. The most common approach revolves around assessments of terrorist messages, yet typically treats those messages as self-serving propaganda or media manipulation. This study takes a different approach, suggesting that terrorists use statements and communiqués in an effort to gain and maintain a supportive audience. Further, the intended audience for the messages infer meaning in terrorist violence, thus augmenting or reducing the impact of persuasive messaging by the terrorist. Understanding this process, in turn, may yield new insights into the dynamic processes of terrorism, offering new opportunities to assess a terrorist group's potential for positive evolutionary growth or greater relative fitness.

 Using Grunig's situational theory of publics, this study creates and evaluates a new metric, called expected affinity, for examining the terrorist group's effort to establish and strengthen bonds between itself and its targeted and presumptively supportive audience. Expected affinity combines sub-measures addressing problem recognition, expected and desired levels of involvement, and constraint recognition, coupled with an inferred meaning in the symbolism of violent acts in order to evaluate terrorist messages and attacks. The results suggest utility in the expected affinity metric and point to opportunities for making the measure more directly applicable to specific cases through incorporation of detailed case study data.