Essential value is a novel measurement of the value of reinforcers, first defined by Hursh and Silberberg (2008) in an exponential model. It measures a fixed rate of behavioral change relative to the change of cost paid to attain a reinforcer. As the given percentage of cost went up, the lower the fixed rate of behavioral change, the higher value of reinforcers, and thus the higher was essential value. This measurement is more advanced than other measurements of the strength of reinforcement, and has been documented empirically by experimental data based on animal food consumption, human drug usage and human economic consumption (Hursh & Silberberg, 2008; Christensen et al., 2008a; Christensen et al., 2008b; Christensen et al., 2009; Yan et al., 2012a, 2012b). Understanding this advanced measurement of the value of reinforcers is important for the Behavioral Perspective Model (BPM) (Foxall, 1990/2004), since essential value not only measures the value of reinforcers but also indicates the demand response sensitivity pattern by comparing the value of reinforcers across different behavioral settings (open vs. closed), different types of reinforcement (utilitarian and informational), and brand groups.