A great way to understand where people will have difficulty using a system is to describe each of the steps necessary to operate the system. Steps have sub-steps. To get to New York, I have to drive; to drive I have to get into my car; to get into my car I have to unlock the door; to unlock the door I have to take out my keys; to take out my keys I have to reach into my pocket; to reach into my pocket I have to angle my hand just so … meaning that if I cannot angle my hand just so, I can’t get to New York. To use even a simple new product requires a complex hierarchy of actions, and each can go wrong for a variety of reasons. Carefully outlining each step by analyzing the cognition, perception, and action necessary to successfully accomplish that step begins the creation of a task analysis. Considering the risks that may occur if there is a problem at each sub-step can help us understand and predict where important problems are likely to occur. This breakdown can also help us verify that problems are designed out and that the associated risks are mitigated as low as probable.