The purpose of this paper is to develop an influence-effect model as a construct for determining information asymmetry influencing factors between suppliers and customers. In order to understand the cause-effect principle of the influencing factors, the principal-agent theory is used to characterize the supplier purchaser relationship. The analysis of supplier evaluations enables the indirect derivation of information asymmetry influencing variables. Social, legal, or the internal influencing issues of companies (e.g., integrated management systems, cooperating systems, etc.) are determined as information asymmetry influencing factors. An explanatory model is designed to determine the information asymmetry influencing variables. The paper provides a structured overview of the main information asymmetry variables that can be assigned in general, but in particular to food supply chains.