This is just one of the models we use and practically apply to different team settings to help our clients move forward, whatever their end-goal may be. When knowing which signals, or symptoms even, too look for, one can identify indicate which stage a team currently is in and by that help them create necessary conditions to move forward.
To hear Dave Sibbet himself explain the origins of the theory, have a look here. You can also learn more here. If you are interested in how to help your teams be the best they can be, we suggest you have a look, or at least ask us more about how to use this model practically.