Abstract Collecting ideas through crowdsourcing has become a common practice for companies to benefit from external ideas and innovate. It is desirable that crowd members build on each other's ideas to achieve synergy. This study proposes and verifies a new method for idea combination which can result in combined ideas that are both novel and useful. The domain-specific knowledge of crowd members does not influence the effectiveness of such idea combination. The new method can be used for collecting highly creative ideas from the crowd. The implications for future research are discussed.