The subject of measuring the performance of registries has been a topic of policy discussions in recent years on the regional level due to the recast of the European Union (EU) port state control (PSC) directive which introduces incentives for flags which perform better. Since the current method used in the EU region entails some shortcomings, it has therefore been the subject of substantial scrutiny. Furthermore, the International Maritime Organization (IMO) developed a set of performance indicators which however lacks the ability to measure compliance as set out in one of its strategic directions towards fostering global compliance. In this article, we develop and test a methodology to measure flag state performance which can be applied to the regional or global level and to other areas of legislative interest (e.g. recognized organizations, Document of Compliance Companies). Our proposed methodology overcomes some of the shortcomings of the present method and presents a more refined, less biased approach of measuring performance. To demonstrate its usefulness, we apply it to a sample of 207,821 observations for a 3 year time frame and compare it to the best know current method in the industry.