Knowledge of Geographic Information Systems is quickly becoming an integral part of the natural resource professionals' skill set. With the growing need of professionals with these skills, we created an advanced geographic information systems (GIS) exercise for students at Clemson University to introduce them to the concept of error analysis, stream delineation, model iterations and feedback loops. The objective of this study was for students to understand how error analysis works within a GIS and for them to be able to perform the analysis on their own, without instruction, once the exercise was completed. In this exercise we instructed students in creating an ArcGIS model in ModelBuilder that created a probability surface model, aimed at predicting the most likely location of a stream network when incorporating inherent error from the initial elevation model. Random amounts of vertical error were included in the model by generating a random raster with specified bounds, and students learned how to perform multiple iterations of a model with the use of feedback loops. Feedback from students was collected during an in class anonymous survey. Students found the exercise to be exceptionally useful for both explaining what error analysis is, as well as how to perform the analysis in ArcGIS Desktop. On average, most students felt they would be able to apply what was learned from the exercise to their own projects in the future with little to no instruction. Furthermore, students felt the exercise was useful in learning about error analysis within a GIS. (Contains 2 tables and 4 figures.)