This article addresses the fundamental element of non-discrimination provisions, i.e., the comparability analysis. Comparisons of treatment between different persons, goods, services, and capital that are present within a specific market are necessary to ensure a level playing field for competition within a globalized world. Comparability analyses are often the deciding factor of cases, and thus a thorough understanding of how they work is essential for practitioners and academics alike. This kind of test is present within several types of international treaties and is often the subject of intense debate and discussion within case law. This is in spite of the fact that there are few cases in which comparability is assumed without any type of analysis whatsoever. This work performs a comparative analysis of comparability analyses throughout the different international regimens of the European Union, Investor-State Dispute System (ISDS), and World Trade Organization (WTO) within the context of tax disputes. For each, it considers the peculiarities of the system, analysing case law, and proposes a way to further the fairness and specificity of comparability analysis. It also proposes the possible implementation of a different comparability analysis based on the impact on value created by companies from a given measure. Comparability analyses, EU, WTO, ISDS, ROIC, transfer pricing, international taxation, dispute resolution, litigation, likeness.