Advanced human-system interface (HSI) technology is being integrated into existing nuclear plants as part of plant modifications and upgrades. The result of this trend is that hybrid HSIs are created, i.e., HSIs containing a mixture of conventional (analog) and advanced (digital) technology. The purpose of the present research is to define the potential effects of hybrid HSIs on personnel performance and plant safety and to develop human factors guidance for safety reviews of them where necessary. In support of this objective, human factors topics associated with hybrid HSIs were identified. A human performance topic is an aspect of hybrid HSIs, such as a design or implementation feature, for which human performance concerns were identified. The topics were then evaluated for their potential significance to plant safety. Twelve topics were identified as potentially safety significant issues, i.e., their human performance concerns have the potential to compromise plant safety. The issues were then prioritized and a subset was selected for design review guidance development. 6 refs