Conceptual modeling is currently considered a significant phase in information systems development. Several modeling grammars and methods have been studied extensively in the information systems discipline. However, previous research on conceptual models has focused on certain grammar (syntax) or discovering a way to deliver the meaning of a model (semantic) more clearly and completely. With regard to the construct overload issue in conceptual modeling, past studies have had some deficiencies in research methods and even presented contradicting results. The objective of the present study is twofold. First, the authors researched the interaction effect among syntax, semantics, and pragmatics to discover the preferred design, context, and user knowledge with which models are more likely to be understood or interpreted. Second, they performed an experiment to reconcile conflicting outcomes and acquire a more complete and accurate understanding of construct overload. Specifically, the authors focused on understanding the end users' modeling performance between ontologically clear and unclear models. They applied an improved experimental methodology that integrates three features (i.e., syntax, semantic, pragmatic) rather than treat them individually and employs different degrees of domain familiarity in the conceptual model (i.e., familiar domain vs. unfamiliar domain). The result of this study will broaden the perspective on usability in the context of the conceptual model and may serve as a modeler's ontological guidance in terms of whether or not to contain construct overload when they create a model. In addition, this study makes the theoretical contribution by verifying the domain extensibility towards the theory of ontological clarity.