The most effective modeling technique in VanLehn (2013) for students modeling the spread of the Zika virus is agent-based modeling, a paradigm explored in detail in this class. Agent-based modeling allows students to isolate the individual classes of agents in a system and program their behaviors, which is vital when each agent (humans, mosquitos at different life stages) has a wide range of behaviors. Also relevant to successful agent-based modeling in VanLehn is the use of virtual labs and virtual field studies. This allows students to manipulate the factors at play and visualize the effects of each agent on the system as a whole.
VanLehn also proposes scaffolding by decomposition into subsystems, an activity that would help students understand better. The life cycle of mosquitos should be modeled as a subsystem on its own, human interactions should be modeled as a subsystem to see which behaviors cause the spread of Zika and mosquito interactions with humans should be modeled to see which interactions result in the spread of Zika either from mosquito to human or human to mosquito.
Another form of scaffolding in VanLehn that be effectively applied to modeling Zika is the "meta-tutoring" through the use of Betty's Brain. Betty's Brain can work by asking students guiding questions, but more importantly can force students to ask explorative questions of their own in order to fully test their models. However, VanLehn notes that it is quite difficult to get students to ask substantive questions beyond verifying answers, a problem that should be explored further.