This paper estimates the effect of a patent grant on the likelihood that an invention will progress to different commercialization stages using survey data on 3,162 inventions which have been the subject of a patent application. We found that about 40 percent of all inventions advanced to the point of market launch and mass production. Although a patent grant had no effect on the decision to proceed with the commercialisation process, being refused a patent lowered the probability of attempting market launch and mass production by 13 percentage points. Somewhat surprisingly, there was minimal evidence that patents were more important for firms which lacked manufacturing capabilities.