To increase the likelihood for software project success, it is important to be able to identify the drivers of success. This paper compares three methods to identify similar projects with the objective to predict project success. The hypothesis is that projects with similar characteristics are likely to have the same outcome in terms of success. Two of the methods are based on identifying similar projects using all available information. The first method of these aims at identifying the most similar project. The second method identifies a group of projects as most similar. Finally, the third method pinpoints some key characteristics to identify project similarity. Our measure of success for these identifications is whether project success for these projects identified as similar is the same. The comparison between methods is done in a case study with 46 projects with varying characteristics. The paper evaluates the performance of each method with regards to its ability to predict project success. The method using key drivers of project success is superior to the others in the case study. Thus, it is concluded that it is important for software developing organizations to identify its key project characteristics to improve its control over project success.