Economic assessment is critical to international commercial law reform in order to ensure law reform efforts are evidence-based and result in economic benefit. Yet, such assessment is seldom undertaken and, when done so, is not uniform in its scope or methodology, nor is it subject to systematic review. This article proposes a set of guidelines in order to address this challenge. While there are both political and technical challenges to law reform efforts and the implementation of a clear framework for assessment, this article aims to provide a first step forward towards creating a unified approach. It does so by proposing a series of guidelines which traverse five key components of any economic assessment undertaking, drawing on international and within country data regarding assessment processes. There is a particular focus on quantitative analysis, replicability, transparency, and continuous improvement, in relation to unifying private international law within the commercial sphere.