<p>RATS (Random-Accessible Text Systems) was a PL/I utility for text analysis developed by John B. Smith of Pennsylvania State Univeristy in the early 1970s. It was aimed at researchers with some experience with programming and aimed to streamline the text analysis process while permitting users to customize the program to suit their work. As a system, Smith promoted RATS for concordences, thematic distributions and transitional matrixes.</p>