<p>Most STEM classrooms overlook the intrinsic conceptual structure of domain content, strategies for improving students’ conceptual structure have promise for improving STEM learning outcomes. This experimental investigation continues the development of the web-based tool <i>Graphical Interface of Knowledge Structure (GIKS)</i> that provides immediate formative feedback as a network of concepts in the student’s essays alongside an expert referent network for comparison and reflection. What should this feedback network look like, especially, should it be more inclusive or small and focused? And is preexisting domain knowledge important for type of network feedback effectiveness? Undergraduate students in a second year Architecture Engineering course, after completing a 2-weeks long lesson on Building with Wood, were randomly assigned to a summary writing task with either Full feedback (a network with 14 central and 12 peripheral terms) or Focused feedback (a network with only the 14 central terms), and then immediately completed a knowledge structure survey. Two weeks later, they completed an End-of-Unit posttest that consisted of a Central-items and a Peripheral-items subtests. A significant interaction of feedback and domain knowledge was observed for post knowledge structure, the low domain knowledge students in the Focus feedback group had the most central link-agreement with the expert and the least peripheral links agreement. On the End-of-Unit declarative knowledge posttest, there was no difference for the Full or Focused feedback interventions, but the high domain knowledge students in both interventions performed significantly better than the low domain knowledge students on the central-items subtest but <i>not</i> on the peripheral-items subtest. This investigation shows the need for further research on the role of domain-normative central concepts and pragmatically contributes to the design of essay prompts for STEM classroom use.</p>