CIMM DEFINITION: The degree to which people who shop at different stores exhibit markedly different responses to a creative execution or exhibit a substantially different pattern of purchase response based on the program types in which they see this commercial execution. (Source: TRA)

NOTE – TRA has yet to observe or quantify this hypothetical type of error; TRA hypothesis is that such error is minimal based on homogeneity of response to creative across shoppers at different stores; to be studied.