John Reitz suggests the following basic principles of the comparative method in John C. Reitz, How To Do Comparative Law, 46 American Journal of Comparative Law 617 (1998).
- Comparative law involves drawing explicit comparisons, and most non-comparative foreign law writing could be strengthened by being made explicitly comparative.
- The comparative method consists in focusing careful attention on the similarities and differences among the legal systems being compared, but in assessing the significance of differences the comparatist needs to take account of the possibility of functional equivalence.
- The process of comparison is particularly suited to lead to conclusions about (a) distinctive characteristics of each individual legal system and/or (b) commonalities concerning how law deals with the particular subject under study.
- One of the benefits of comparative analysis is its tendency to push the analysis to broader levels of abstraction through its investigation into functional equivalence.
- The comparative method has the potential to lead to even more interesting analysis by inviting the comparatist to give reasons for the similarities and differences among legal systems or to analyze their significance for the cultures under study.
- In establishing what the law is in each jurisdiction under study, comparative law (and, for that matters, studies of foreign law, as well) should (a) be concerned to describe the normal conceptual world of the lawyers, (b) take into consideration all the sources upon which a lawyer in that legal system might base her opinion as to what the law is, and (c) take into consideration the gap between the law on the books and law in action, as well as (d) important gaps in available knowledge about either the law on the books or the law in action.
- Comparative and foreign law scholarship both require strong linguistic skills and maybe even the skills of anthropological field study in order to collect information about foreign legal systems at first hand, but it is also reasonable for the comparative scholar without the necessary linguistic skill or in-country experience to rely on secondary literature in languages the comparatist can read, subject to the usual caution about using secondary literature.
- Comparative law scholarship should be organized in a way that emphasizes explicit comparison.
- Comparative studies should be undertaken in a spirit of respect for the other.
Edward J. Eberle suggests the structured comparative law methodology in Edward J. Eberle, The Methodology of Comparative Law, 16 Roger Williams University Law Review 51 (2011).
- Acquiring the skills of a comparatist in order to evaluate law clearly, objectively, and neutrally.
- Evaluating External Law, as Written or Stated.
- Evaluating the law as it is expressed concretely, in words, action, or orality.
- Evaluating Internal Law (or Law in Action).
- Evaluating how the law actually operates within a legal culture.
- Determining Comparative Observations
- Assemble the results of our investigation and conclude with comparative observations that can shed light on both a foreign and our own legal culture.
Mark Van Hoecke proposes a toolbox, rather than a fixed methodological road map, for comparative law research in Mark V. Hoecke, Methodology of Comparative Legal Research 1 (2015). He distinguishes six different methods for comparative research.
- The functional method is looking at the actual societal problem and the way this is solved in different jurisdictions along similar or different roads and with similar or different results. The focus is on the societal problem and the actual result of the legal approach to that problem.
- The analytical method is analyzing legal concepts and rules in different legal systems in such a way that common parts and
differences are detected.
- The structural method is focusing on the framework of the law or of the elements reconstructed through an analytical approach. This is not the structure of each of the compared legal systems, but just one way of looking at them, which proves to be revealing for answering the research question.
- The historical method will almost always be a necessary part of the methods used, for understanding differences and commonalities among legal systems and for determining their degree of belonging to a deeply rooted tradition or rather to accidental historical events.
- The law-in-context method has inevitably also a historical dimension but focuses on the law’s current societal context, including, where appropriate, culture, economy, psychology, religion, etc. It studies a much broader context when compared to the functional or analytical method and implies the use of other disciplines.
- The common-core method looks for commonalities and differences between legal systems in view of the question to what extent harmonization on certain points would be possible among the compared legal systems or the question how a European rule, for instance, could be interpreted in such a way that it fits best the different national traditions.
Hoecke also distinguishes levels of comparison as follows:
- Macro level vs micro level:
- Comparing legal systems as distinguished from comparing more concrete rules and legal solutions to societal problems in different legal systems.
- Doctrinal framework vs underlying legal culture:
- Comparing the content of the law (values, principles, or rules) and the attitude towards the law versus comparing doctrinal frameworks as divided into the Common Law system and Civil Law system.
- Surface level vs deep level:
- Looking at superficial similarities and/or differences among legal systems, as compared to studying diverging types of ‘right’ included in complex legal concepts, rules and institutions, underlying world views, a detected common structural framework behind apparent differences, elements in history that are weakening the strength of seemingly opposed and irreconcilable approaches, etc.