A series of psychological processes through which a person becomes aware of a new product or service and ultimately chooses to adopt or reject it. Hierarchy of effects models can be used to forecast behavioral changes, such as programs to reduce smoking. These processes consist of sequential stages, including awareness, knowledge, liking, preference, and choice. Forecasting models can be developed for each of these stages by including policy variables critical to that stage (e.g., promotions for awareness, informational advertising for knowledge, and comparative advertising for liking).