I am currently writing my proposal and I wanted to define a duration period for my pilot study. My pilot study will be a "feasibility" study and it will help me to define a couple of things for the main study. My main study is a year-long intervention with children with autism. So, how can i determine the pilot study's duration? And maybe if you can suggest me some theses that has a pilot and a main study in it, just to see how it is formed, I would be much appreciated. Thank you :)