Model-based approaches to cognitive task analysis rely on abstracting from the problem domain, rather than a description of task performance. Various classes of work analysis models can be distin-guished: task models, work domain structure models, and work domain goal models. In this article, we discuss 3 specific model-based approaches: the Abstraction Hierarchy (AH), Multilevel Flow Modeling (MFM), and the Decision Ladder (DL). The AH creates a model of the work domain struc-ture, MFM of work domain goals, and DL of actor tasks. The 3 approaches are compared in the context of a common example—that of a power plant boiler—to show clearly the differences among the 3 classes of techniques.