The key tasks in the design of a choice modelling (CM) experiment are to define the scope, scale and frame of the tradeoffs presented to respondents. This study explores the scale and scope of choice tasks and then develops definitions of these terms. The scope of a good in a stated preference experiment refers to the dimensions used to define the good as well as the tradeoffs involved. The scale refers to the quantities involved. The framing refers to the context in which the choices are made. The discussion helps identify issues when setting the contingent market for a choice experiment.