One way to define a pattern within a phase is in terms of the level of behavior. The term level simply refers to the magnitude of the participant’s responses. If all of the observations within a phase indicate approximately the same magni- tude, or level, of behavior, then the data have demonstrated a consistent or stable level of behavior within the phase. Figure 14.2a shows data demonstrating a sta- ble level of behavior. Although there are minor differences in magnitude from one observation to another, the data points generally line up at the same level of magnitude. Notice that the concept of a stable level simply means that the data points within a phase tend to form a horizontal line on the graph.