Easy: Hi-Q CQC is easy to learn, easy to practice, and easy to recall during a hostile encounter. 

Effective: Hi-Q CQC is effective because it develops officers abilities to respond efficiently during a variety of altercations.

Stimulus Response Conditioning: The key to Hi-Q's simplicity and effectiveness is Stimulus Response Conditioning.  In training, officers drill simple and practical, gross motor skill responses to a variety of stimulus that they may encounter.  Through this process, officers develop a conditioned response.  During an actual altercation, their training dictates an appropriate and effective response.  This process also allows officers to justify their responses to specific stimulus.