Linkages between the theoretical world and the empirical world to which it applies are made through the formulation and testing of hypotheses. Both scientists and practitioners use this process to make the empirical world and the theoretical world as congruent as possible. It is important to distinguish an empirical system from a theoretical system. An empirical system is what we apprehend, through senses, in the environment. A theoretical system is what we construct in our mind's eye to model the empirical system.1 Nurse scientists and practitioners focus on understanding the variables of a particular practice situation. To better understand a specific event, they formulate working definitions and associations among variables (hypotheses) and either develop a new theoretical system or link them to existing organizing frameworks. The theoretical system then serves as guidance about how to proceed, and as long as the abstraction of a theory can be represented with empiric indicators, hypotheses can be generated and empirically tested.2