Legal Education Compared
In the U.S., the customary way that one learns about the law for purposes of being admitted to practice as a lawyer is by completing three years of course (with no thesis or dissertation) at the graduate level, after completing a non-law related undergraduate degree (customarily four years but including non-legal studies), and then taking a several week bar exam preparation course and passing the bar exam.
In many other common law countries, the customary way that one learns about the law for purposes of being admitted to practice as a lawyer is by completing a three or four year preprofessional undergraduate degree, with a primary concentration in law but also including other general education requirements, followed by preparation for and sitting for a bar exam, and sometimes a period of apprenticeship or internship.
In most civil law countries, the customary way that one learns about the law for purposes of being admitted to practice as a lawyer is by completing a bachelor's level undergraduate degree which is taken by both people who want to become practicing lawyers and also by people who want to go into business with legal knowledge, followed by very extensive bar exam preparation in the context of an internship or apprenticeship somewhat similar to that of a U.K. barrister.
This is complicated somewhat by the fact that the U.K. and most civil law countries have multiple different legal professionals rather than a unified legal profession like the U.S. The U.K. has barristers (trial advocates) who have more education through the "inns of court" and solicitors. Civil law systems typically have more kinds of legally trained professionals with legally trained notaries with transactional law practice infused with the keeping of public records, prosecutors, judges, trial advocates, sometimes specialist public law lawyers, and legally trained non-lawyers (typically in business) all belonging to separate professions with different roles in the legal system.
No entry level lawyer who has been admitted to practice knows the whole of the law in the country where that student has studied, and generally, even very experienced lawyers will be experts in some parts of the law, and have only a vague notion of where to learn the law in other areas where the lawyer practices only infrequently or not at all.
In common law countries, legal education focuses on "edge cases" and the way that edge cases are argued, and leaves instruction to many "black letter" rules of law to be learned in bar exam preparation and after entering the practice of law to learn on the job.
In civil law countries, legal education focuses on providing students with a comprehensive outline of the "black letter" law rules of law in the area of private law and criminal law and a few bits of public law, and learning methods of argument, advocacy and edge cases is reserved for learning on the job in practice.
In both systems, the primary way that one learns the law as a future lawyer in the first instance is from textbooks, rather than primary authorities, although common law country law school textbooks have a heavier mix of excerpts from court cases selected by a professor, while civil law country law school textbooks have a heavier mix of statutory language excerpts and exposition form the professor writing the textbook.
Lay Understanding Of Particular Areas Of Law
Please estimate: what is the difference in amount of work needed in
these two systems to become familiar with an area of law? Please
estimate for a well-educated person (with a college degree or higher)
but is not a lawyer and does not plan to become one.
A well-educated person with a college degree or higher but is not a lawyer and does not plan to become one faces a very steep learning curve in either system to become familiar at a functional level with an area of law.
Most of what a lawyer learns in school is the larger context and method of analysis, research skills and an ability to identify legal issues. In common law countries, a lot of this is learning how the case law making system works and having an unwritten outline of key issues in areas of law that would be codified in civil law countries. In civil law countries, a lot of this is learning how general parts of civil law codes interact with more specific provisions, and being aware of the "gloss of interpretation" (often in scholarly work by law professors) that is given to a superficially very vague and short provision like the section of a civil code imposing tort liability, and also how to research legal issues in that system.
You really need to know all of this general material to have a competent and comprehensive understanding of specific legal issues, whether you have one that you are investigating or twenty. So, it is extremely inefficient for a non-lawyer to master a single legal issue.
The difference in the learning curve between civil law systems and common law systems from pure primary sources is greatly reduced because both are intermediated by secondary sources that explain them in a more efficient and pedagogically sound manner.
Rather than largely being a difference between say, the French system and the Colorado system, for example, the biggest difference in the learning curve involved the nature of the particular legal issue that you want to know about within a particular system.
For example, in both the U.S. and in France, the body of law that governs child custody and child support is very self-contained. If you master the legal principles and authorities in that area of law, you can fairly swiftly know all of the substantive law issues and research issues involved.
On the other hand, in both the U.S. and in France, the body of law that governs a property division in a divorce is absolutely sprawling. This is not because the law of property division itself, in sensu stricto, is terribly vast, but because applying the relatively simple law of property division to any set of facts, presupposes and requires a comprehensive knowledge of the private laws of property, contracts and other legal obligations, and associated tax laws, which can be quite vast over the full range of legal and property rights the might need to be divided in some divorce, sometime. It is the opposite of being self-contained.
Similarly, immigration law or patent law questions can often be resolved and understood almost entirely within the four corners of a small number of statutes and regulations, while tax law questions, like property divisions in divorces, interface with a vast expanse of property, contract and legal obligations that might arise.
As a general rule, laws pertaining to personal status tend to be self-contained, while laws in areas implicated property ownership and legal rights more generally, tend to require an expansive knowledge of many areas of law.
Starting From Scratch
While codification v. case law doesn't make much of a difference in the amount of work needed to become a lawyer or to understand a particular legal issue, codification does provide a decisive advantage in the case of a country seeking to adopt a new legal system from scratch, and many former European colonies have done, which is why civil law systems are so much more common globally.
From the perspective of a legislature and judiciary starting from a more or less clean slate, it is much easier to adopt a mildly edited set of civil codes as the starting point for the law of your country, than it is to incorporate centuries of case law from some other country into the law in a country that has never used a common law system case law system "organically" prior to adopting its own set of laws. Even then, it is much harder for legislators to be clear on precisely what laws it is that they are adopting at the outset in a common law case law based system where many legal rules are implicit in decisions that are only imperfectly indexed, rather than explicitly codified. And, from a legislator's perspective, adopting a comprehensive new legal system without any clear delineation of what laws you are actually adopting in your new country, is very undesirable, unless you are merely grafting onto a common law legal system that has already long been in force in your country prior to starting its new legal system, with which all prospective legal practitioners in your country are already intimately familiar.