This paper offers a definition for the word "effective" and then discusses implications of research on the environment in relation to designing effective instruction. Similarities and differences involved in designing effective instruction are presented across four different contexts: K-12, higher education, human services, and corporate. The paper posits that the primary reason instruction and training fail to achieve intended goal(s) is due to instructional designers' tendency to overlook or underestimate environmental issues. With this in mind, it is suggested that environmental issues be thoroughly addressed before instructional designers proceed with the design process. A model of E=PxSxS (effective, product, stakeholders, setting) is used to frame the discussion about developing effective instruction or training. (AEF)