Models for numerical simulations should be described in a coherent style. They are expected to have consistencies at the causal dependency level. However, System Dynamics causal loop diagrams can have inconsistencies. This diagram style’s arrows, concerning flow and stock relationships, can have the opposite direction of stock flow diagrams which can numerically simulate models. These inconsistencies can cause inappropriate qualitative simulations so that it is sometimes recommended to use stock flow diagrams instead of causal loop diagrams even for qualitative simulations. However, causal loop diagrams have merits in their use. Causal loop diagrams are intuitively easy to draw and read. If causal loop diagrams are given information about each variable’s dynamic property, they can be changed to stock flow diagrams and simulation models can be generated. This paper suggests how to use causal loop diagrams as a starting point in numerical simulation research.