The term private-collective model of innovation was coined by Eric von Hippel and Georg von Krogh in their 2003 publication in Organization Science. This innovation model represents a combination of the private investment model and the collective-action innovation model. In the private investment model innovators appropriate financial returns from innovations through intellectual property rights such as patents, copyright, licenses, or trade secrets. Any knowledge spillover reduces the innovator's benefits, thus freely revealed knowledge is not in the interest of the innovator.