This study examines the effectiveness of teaching with simulations, compared to active learning without simulations. It utilizes an anonymous extra-credit pop quiz on four topics, each taught with a different method: (1) simulation and in-class debriefing; (2) simulation only; (3) in-class discussions with an accompanying research essay; and (4) in-class discussions only. The study presents a range of assessment techniques used in simulation literature, and suggests the use of the anonymous extra-credit pop quiz as a simple and familiar teaching practice, but an overlooked assessment tool for simulations. The study presents the "Iranian Plane" simulation developed to teach decision making in crisis situations to political science undergraduates. It analyzes empirical evidence on knowledge retention with and without simulations based on students' performance on the pop quiz 3 months after the simulation. The analysis shows that learning with simulation and debriefing together attains teaching goals set in advance. Simulation with debriefing was the most effective teaching mode for knowledge retention in terms of students' performance in the quiz, simulation only was almost as successful, but learning without simulation was less efficient.