4- We had a video-conference with each developer to explain the tasks, show a demo of different tools, and clarifying the process of result submission. The participants attended a live streaming lecture using bluejeans and they all have high experience on refactoring and the used open source systems. We tried to mitigate possible threats by enabling both offline and online questions, recorded video of the lectures, doing two exercises to make sure that they are able to evaluate refactorings, etc.