An article not too long ago in the Journal of Consumer Psychology summed up current research on brand extensions thus:
What factors determine whether or not a brand extension will be successful? The most important factor identified by prior research is perceived fit. Consumers respond more favorably if they are able to perceive a fit between the extension and the parent brand. . . . Perceived fit, no matter how it is defined, is the most important determinant of brand extension success—more important than marketing support, retailer acceptance, and quality of the parent brand.
The last sentence is worth reading again! Marketing support, effective distribution, and even strength of the parent brand matter less than whether buyers think the extension makes sense. (more…)