Summary: Practitioners of CI get a lot more bang for their buck when they spread the process of getting repetitions on the language out over a process of reading the story, as opposed to using circling to get reps during the creation of the story.
You may want to read this if you still use circling as a TPRS/CI tool. Why? It is because if you are still circling you may be making a mistake. The kids don’t like it.
Circling was invented by someone in Blaine Ray’s circle (not exactly sure who it was, maybe Blaine himself) around 2004. I was in the front row of a training here in Denver when he unveiled it.