Robert Mies and Jérémy Bonvoisin are part of a research project team working on open source hardware at Technische Universität Berlin. They are launching a survey to better understand how product development in open source communities works and have a questionnaire that takes about 15 minutes to complete. It is open until 16 Nov 2017 - do consider participating!
For more on the research, visit their wiki page or access their latest article in the Journal of Open Hardware.