Decades of effort has been put into decreasing the high failure rates of introductory programming courses. Whilst numerous studies suggest approaches that provide effective means of teaching programming, to date, no study has attempted to quantitatively compare the impact that different approaches have had on the pass rates of programming courses. In this article, we report the results of a systematic review on articles describing introductory programming teaching approaches, and provide an analysis of the effect that various interventions can have on the pass rates of introductory programming courses. A total of 60 pre-intervention and post-intervention pass rates, describing thirteen different teaching approaches were extracted from relevant articles and analyzed. The results showed that on average, teaching interventions can improve programming pass rates by nearly one third when compared to a traditional lecture and lab based approach.