TEACHING ALGORITHMS AND ALGORITHMS FOR TEACHING.

• Author: Lawsky, Sarah B.

1. INTRODUCTION 588 II. THE ALGORITHM METHOD 589 III. THE WEBSITE 596 A. Introduction to the Website 596 B. A Simple Topic 598 C. A More Complex Topic 599 IV. THE WEBSITE FOR PROFESSORS: ACTIVE LEARNING 602 IN THE CLASSROOM A. Active Learning in Class 603 B. The Problem: Section 453(e) and Losses 607 1. The Installment Method 608 2. The Classroom Problem 612 3. The Policy Implication and the Statute 614 4. The Pedagogy of the Problem 616 5. How This Happened 617 V. THE WEBSITE FOR STUDENTS: INDEPENDENT 618 ACTIVE LEARNING A. Remember the Statute 619 B. Shaping the Student Experience 623 VI. CONCLUSION 625 I. INTRODUCTION

   Common methods of instruction in the law school classroom include the "case method" and the "problem method," each of which requires law students to confront difficult and ambiguous problems in law. U.S. law does include many difficult and ambiguous problems. Less recognized is that some U.S. law, including the Internal Revenue Code and its accompanying regulations, is difficult not only because portions of it are ambiguous but also because it consists of complex interlocking rules. Deciphering even the unambiguous parts of these rules is both difficult and critical to the role of the lawyer.

   Tax classrooms typically use unambiguous problems with objectively correct answers to help students learn how to read these complex rules. Because these problems have objective answers, and because there are clear steps to be followed to obtain these objective answers, students learn to follow algorithms--step by step processes--to solve these problems. A computer program can therefore create such problems, along with useful explanations, and thus allow students to practice solving a very large number of substantively distinct problems that draw their answers directly from the statute. I have written such a computer program, and it is available to both students and professors. The website is helpful to students and teachers in many ways, and it also creates potential issues for both students and teachers. As the Article discusses, some of these issues aren't because of the computer program but rather are issues that may arise whenever students learn complex law by using problems with objectively correct answers.

   After this introduction, Part II describes the "algorithm method" of teaching. Part III describes the website. Part IV explains how professors can use the website to enhance active learning in the classroom and perhaps to create unexpected insights into the law. Part V discusses ways to shape and improve student experiences with both the website in particular and the algorithm method more generally. Part VI concludes.

2. THE ALGORITHM METHOD

   Law school classes in the United States are often taught using the "case method," in which students learn the law by reading and analyzing cases with the assistance of intensive questioning and lecturing by the professor. The "problem method," in which students learn the law by wrestling with how to apply the law to a particular set of facts (a "problem"), is often set in contrast to the case method. In many, perhaps most, law school classes, the problems in the problem method present students with "messy" facts for which there is no single correct legal analysis and ask them to consider a range of perspectives to arrive at and defend a particular conclusion. (1)

   Transactional courses as well as litigation courses can benefit from using ambiguous problems to present material. Heather Field, for example, has described using such an approach in her tax classes. (2) She presents the students with fact patterns that "omit[] a tremendous amount of information"; students are required to "use their knowledge of the substantive tax law...to identify and gather [relevant] facts." (3) They must understand the economics of the deal, weigh the importance of tax as opposed to other issues in the deal, communicate effectively with the client, and so forth. (4) Victor Fleischer has described a similar approach to bringing transactional law into the classroom with experiential learning. (5)

   Because of the complexity of the Internal Revenue Code, however, tax law classes sometimes present the student with unambiguous problems that have objectively correct answers that the student can arrive at by stepping through complex rules. I'll refer to this as the "algorithm method." The algorithm method may seem to be a simplistic approach that is no more than a precursor to presenting more complex and ambiguous problems, but as this Part argues, the algorithm method is on its own an effective and important way to help students learn how to read and understand a complex statute, most notably, for purposes of this paper, the Internal Revenue Code.

   In contrast to the messy, ambiguous problems presented in the usual problem method, the algorithm method asks students to work through unambiguous problems that have right and wrong answers. Correctly answering these problems requires the students to use a step-by-step method with defined inputs and outputs. That is, answering these problems requires the students to use an algorithm. (6)

   The algorithm method is commonly used to teach students statutes, and the problems focus attention on particular portions of complicated statutory language. The algorithm method does not provide the student with "messy" and "open-ended" questions about the questions. Rather, the algorithm method steps the student through the statute to see how the statute unambiguously but perhaps initially confusingly works. (7)

   Using a series of unambiguous problems to guide students through the statute and regulations is an unremarkable, uncontroversial, and common method of teaching tax in U.S. law schools. Many law-school tax textbooks use what they call the "problem method" to guide students through complex statutes. The approach of these textbooks is at least in part what I call the algorithm method. (8) As one textbook explains, "We...believe that the most effective way to teach and learn tax fundamentals is by the problem method....The problems are designed to help students decipher the statute and apply it in a wide variety of alternative fact situations." (9) The "problem method" here is the algorithm method because the problems help students work through and understand unambiguous and complicated portions of statutes.

   The algorithm method as a pedagogical approach may initially seem difficult to defend. Why should students learn how to execute an algorithm when an algorithm is a predefined series of steps and may well be able to be applied by a computer? As Jordan Ellenberg writes, executing certain algorithms "is something a computer can do quite effectively." (10) A teacher who does no more than teach the algorithm and how to execute it "is essentially training the student to be a very slow, buggy version of Microsoft Excel." (11)

   While it is not useful to teach students to be a slow, buggy version of Excel, it is useful for students to learn to evaluate when to use a particular algorithm--that is, when to apply a particular statute--and think about whether the application of the statute provides an answer that makes sense when considered in the context of the statute, the Code, the legislative history, the policy that was meant to be implemented, as well as normatively. As Ellenberg explains about teaching algorithms in a math class: "Understanding whether the result makes sense--or deciding whether the method is the right one to use in the first place--requires a guiding human hand. When we teach...we are supposed to be explaining how to be that guide." (12)

   The algorithm method is also critical for tax classes because the algorithm method can be an effective way to teach students how to read statutes. The tax statute and regulations raise difficult and ambiguous questions, of course. A law school tax class would fall short if it used only the algorithm method for teaching the entire class, never highlighting the deeply difficult questions in the tax law, questions that cannot admit of a clear, unambiguous answer. Nonetheless, for someone learning a tax topic for the first time, even getting to the point of understanding what makes a question truly difficult and ambiguous may require deciphering complex and initially difficult, although itself unambiguous, material. Not all initially difficult questions in tax law, that is, are difficult because they are standards and not rules. (13)

   Reading a statute is not the same as reading other difficult and complex texts. Consider, for example, a post on a popular philosophy blog regarding a proposed change in tax law. The post presents its struggle in its very title: "Tax Proposal Would Make Getting a PhD in the US Very Expensive (Multiple Updates)." (14) In this post and the following comments, philosophers are unable to read a fairly straightforward provision of the tax Code and proposed legislation amending it. They deem some questions that are clearly answered in the statute to be ambiguous and open to interpretation; they deploy predicate logic to reach wrong answers; they say, describing an incorrect reading, that given the language of the statute "this is the right way to read" the section; they use predicate logic to support a statement that they really "don't see any other way to read this code"; and so forth. Philosophers are, if nothing else, supposed to be experts in reading complicated texts. But reading statutes is a distinct skill that is acquired only through targeted practice and learning.

   The algorithm method can help teach students the specific skill of reading statutes by focusing students' attention on the specific language of the statute and how the different parts of the statute interact to provide an outcome. A fact pattern can guide a reader through various aspects of a particular statute and focus the reader on phrases and interactions that might otherwise go unnoticed--hence, the...