I found the inspiration in the following paper: Sethuraman R. (2000). What makes consumers pay more for national brands/ Image or Quality, Marketing Science Institute, report Nr. 00-110. In this study the focus was mainly on the quality perceptions of store brands. The model explained about 20 % of the variance in the premiums.
Our research investigates the influence of categoric characteristics like perceptions of risk and expressive value, besides the quality perception of store brands. Hopefully these variables help to explain the premiums people pay for national brands over store brands.