Abstract: Models, as the main artifact in model-driven engineering, have been extensively used in the area of embedded systems for code generation and verification. One of the most popular behavioral modeling techniques is state machine. Many state machine modeling guidelines recommend that a state machine should have more than one state in order to be meaningful. However, single-state state machines (SSSMs) violating this recommendation have been used in modeling cases reported in the literature.We study the prevalence and role of SSSMs in the domain of embedded systems, as well as the reasons why developers use them and their perceived advantages and disadvantages. We employ the sequential explanatory strategy to study 1500 state machines from 26 components at ASML, a leading company in manufacturing lithography machines from the semiconductor industry. We observe that 25 out of 26 components contain SSSMs, making up 25.3