Ground water models are considered an essential part of water resource studies. Yet the current methods of analysis and complexity of the systems often leave those funding the studies wondering exactly how the results improve their resource management. For example, have ground water modeling efforts benefited or suffered from the dominance of a handful of codes such as MODFLOW, MT3DMS, and PHREEQC? How are graphical-user interfaces improving or confusing modeling? How is inverse modeling helping or hurting? What is the right balance between simplicity and complexity? This session focuses on identifying problems that cast doubts on the credibility of modeling and ways to address the problems to render modeling more effective. Presentations are from engineers and hydrogeologists in academia, government, and industry including those engaged in applied, experimental, and theoretical endeavors, as well as specialists in new methods of data collection and integration into modeling projects.