The observations last anywhere from two to forty-five minutes, and are intended to support the faculty in the delivery of instruction and curriculum.[10] Carolyn Downey is known for her early work in the development of the classroom walkthrough model, however, there are several models available and some school districts have created their own. The aim of the classroom walkthrough is to provide direct and specific feedback to teachers based on the snapshot observed. The feedback can then be given to an individual, or the observer may provide a report of patterns noted during the walkthroughs.[11] According to the National Staff Development Council, walkthroughs, sometimes referred to as "learning walks," provide the opportunity to: