This study aims to identify the factors fostering radical innovations during new product development (NPD), and investigate into the importance of customer involvements. Based on an analysis of a large number of relevant research, the hypothesis is established: H1, The customer is not the most or the only significant factor affecting radical innovation performances in NPD. To test H1, an interactive multiple regression model is adopted to detect the impacts of innovation-related factors. Through calculation and comparison, the results showed the radical innovations are more sensitive to professional consulting institutions such as ‘consultants, commercial lab or private R&D institutions’ rather than ‘customers, clients or end users’. Based on the analysis, conclusions are drawn that firms should properly distribute research focus on all important aspects, and carefully control the customer involvements so as to achieve the best benefits.