The Legal Analyst Synthesist
A condensed guide to the instruments in a lawyer’s conceptual toolkit.
Rob James
April 25, 2025
Ward Farnsworth, University of Texas law professor and former dean, wrote a book while at Boston University entitled The Legal Analyst: A Toolkit for Thinking About the Law (2007). It is a rich book that appeals to me, but I find it difficult to navigate. Part of the reason is that the author tends to start each chapter unfolding an example, and only later telling the reader what concept is being illustrated. The reader has to re-read the chapter to apply and internalize the concept.
Farnsworth is an enthusiast for the Socratic method (and has extolled its virtues in another book). But a practicing lawyer like me has long grown weary of a professor’s hiding the ball. Here, I offer a synthesis of the analysis—a Gilbert’s crib to his Kingsfield impersonation (see John Jay Osborn, Jr., The Paper Chase (1971)). I explain each concept alongside its relevant examples (either his or mine). My goal is to encourage more use of this excellent resource for lawyers of all vintages.
Preface
Farnsworth notes that in law school, we learn legal rules (like the requirements for contract formation, the elements of the negligence cause of action, or the difference between murder and manslaughter) and legal tools (ways of thinking, either taken from within jurisprudence or borrowed from other disciplines like economics or psychology). The rules are taught in subject-specific classes and texts, but the tools are not covered as their own topic. Instead, individual tools show up unsystematically from time to time in the curriculum.
The book omits tools associated with moral theory, critical legal studies, legal realism, constitutional interpretation, textualism, and “social norms.” Rather, it covers (I) incentives that legal decisions have on choices, (II) problems of trust and cooperation in working with others, (III) jurisprudential concepts like the slippery slope and the optimal design of rules, (IV) psychological concepts responding to irrational behavior, and (V) evidentiary concepts relating to proof and presumptions. Let’s go!
I. INCENTIVES
1. Ex Ante and Ex Post. A bank robber demands cash, and when the teller refuses the robber shoots a customer; the customer’s estate sues the bank. After the fact (ex post), you might think this bank should be liable for not obeying this demand to pay money in order to avoid this death, but before the fact (ex ante), you might think that such a liability rule in general would lead to more bank robberies and more hostages. It is tempting to have a rule to pay this victim, but perhaps not if such a rule applied everywhere would lead to many more victims.
2. Efficiency. In a lawsuit, you have only so many days to file a brief, you must include all arguments you wish to make, and you must timely object to a judge’s ruling on admission of evidence or testimony. If you are late or fail to preserve your argument or objection, you are out of luck. Another example: we could eliminate all accidents if we had a 5 mph speed limit, but we would never get anything done. That is why we have a standard of negligence rather than strict liability in many tort realms; we want the right investment in safety, not an overinvestment in safety at the expense of other goals. A third example: we like to confer ownership of any item on someone, so that someone has incentives to use it and care for it. The common concept is efficiency, the minimization of costs in the long run. We put decisions and things in the hands of those who will value them the most, or who will suffer the most from their poor use. Design rules so that waste is minimized in the long run, even if some losses are suffered in individual cases.
3. Thinking at the Margin. A tax on cigarettes will not dissuade everyone from smoking, true, but it will dissuade some people. Partisans in a dispute usually want all or nothing (in a land-use dispute, wanting either no airport at all, or no flight restrictions at all). But legal decision-makers may use marginal thinking to provide substantial benefit without so much restriction that substantial losses occur. (In the land use case, perhaps reduced flights at certain times of certain days.)
4. Single Owner. Ask what would happen if an activity currently broken out between multiple people was entirely conducted by one person. Design a legal rule that replicates what such a single owner would do. The concept of general average in maritime law is that all the cargo and vessel owners share in the cost of items thrown overboard to prevent capsizing.
5. Least Cost Avoider. I heard this as the “cheapest cost avoider.” An argument for strict liability is to impose liability on the party best able to bear a risk, minimize that risk, or transfer or insure against that risk. For example, an employer is considered better able to absorb and transfer risk of injuries to or by employees in the course of their employment, hence we have respondeat superior.
6. Administrative Cost. All other things equal (ceteris paribus, which they rarely are!), seek to reduce the costs of implementing and administering a legal rule. A statute of limitations is such a rule. An argument for an “objective” test or measure of damages is that it is cheaper to implement than a “subjective” one that requires inquiry into intentions, state of mind, or a plaintiff’s peculiar sensitivities. (It is not always easy to sort tests between objective and subjective.)
7. Rents. In Farnsworth’s conception and I guess in economic literature, a “rent” is any wasteful activity undertaken to gain a prize, or “competition over the way some good thing ought to be distributed.” If there is a buried $1 million treasure and twenty groups each spend $500,000 trying to find and recover it, that is a social waste. I don’t see this definition anywhere in the legal literature; I am aware from antitrust law of a more limited definition of “rent,” namely the excess price charged by a monopolist over the marginal cost of the good. This chapter would be better titled simply “Waste.” In any event, one should design legal rules so they do not reward wasteful activity. A finders-keepers rule for buried treasure might produce such social waste, so grant rights to the first party that spends real money and don’t let a last-minute interloper swoop in to claim the trove.
8. Coase Theorem. Implicit, not express, in a famous 1960 Journal of Law & Economics article. Can be stated: “In a world with no transaction costs (i.e., parties can identify each other and costlessly bargain and contract with one another), the allocation of rights and duties by the legal system does not matter—the rights will flow to whomever values them the most and to whoever pays the most.” But we don’t live on that planet—we do have transaction costs! Nonetheless, one can imagine what the result might be—who would pay for the right to engage in an activity. Closely related to the puzzle of legal causation. Which is the cause of a crop fire—the railroad that throws sparks on a nearby crop of wheat, or the wheat that is grown close to the train track? In a frictionless world, maybe the railroad would pay the farmer to bear the risk or plant his crops a little further back, and thereby let its trains keep sparking away. Maybe create a legal rule that leads to the same result—a right for the railroad to operate, subject to an obligation to pay the neighboring farmer or to compensate the farmer to relocate its plantings.
II. TRUST AND COOPERATION
9. Agency. An agent doesn’t get all the benefit of his activity, since most of it goes to the principal. Thus he has incentives to shirk, to conceal benefit, or to self-deal. Monitoring for bad agent behavior is costly, but so is a good agent’s effort to justify and defend himself—the sum of these two is referred to as “agency costs.” One can design rules to reduce the need for monitoring or justification, thereby minimizing agency costs. Dividing waiters’ compensation between salary and tips is said to encourage good localized service and higher overall revenues.
10. The Prisoner’s Dilemma. A situation in which coordination and cooperation between actors would lead to a better result for each, but lack of communication means each chooses an action that is suboptimal. Confessions by two criminals are the classic example—if they both keep mum they get off, but if one confesses and the other doesn’t the confessor will do better than if it’s the other way round, so they confess and both are worse off. As a company nears bankruptcy its creditors might be better off if all of them refrained from seizing key assets, but will each of them exercise that restraint?
11. Public Goods. A species of the prisoner’s dilemma, apparently. A good that no one person owns and is available to all leads to free-riding. Why bother helping, or taking care of the good, if that good is available without your contribution? These twin topics address the “tragedy of the commons.” This concern is the foundation of intellectual property law, because once an idea or expression is out there, it is available to all absent a special legal rule.
12. Stag Hunt. To hunt big game, like a stag, you need everyone (or almost everyone) to work as a team and to cooperate. If you can’t get everyone (or almost everyone) on board, you might as well just each of you hunt scrawny game, like puny rabbits. Examples: mutiny, overcoming a hijacker.
13. Chicken. Marbury v Madison is an example—who would blink first, the Supreme Court or the Executive Branch? The Court skillfully asserted control, saying it is the branch that interprets the Constitution, but in that case it interpreted the Constitution to allow the Executive to take no action. We are seeing that scenario play out again in 2025.
14. Cascades. A hot restaurant doesn’t lower its prices; it builds on the buzz. “Everyone wants to eat there, therefore everyone wants to eat there.” Making segregation illegal helped the Southern facilities that wanted to serve blacks but feared reprisals (kind of a stretch for this oncept).
15. Voting Paradoxes. Public choice theory (Condorcet the issue, Arrow the formal presentation); issues of deriving a clear outcome out of multiple-choice preference rankings. Shows up in appellate court decisions where different judges value different arguments.
16. Suppressed Markets. We could have an overt market for immigration, but we don’t (yet). It is hard to get into a selective university, but we contain the compensation within its walls; once there it is pretty hard to be expelled. Players thus compete in a hidden tournament. We keep the compensation on the outside rather than continue it within our boundaries. Some cracks in the system appear, like the H-1B visa or proposed $5 million “golden ticket.”
III. JURISPRUDENCE
17. Rules vs. Standards. A rule is that you can’t use testimony if the Miranda rights are not read, and you can use testimony if the rights are read. A standard is that a confession cannot be “coerced.” The distinction between rules and standards is not always that clear.
18. Slippery Slopes. Even if decision number 1 is acceptable it will lead to a parade of “decision n” horribles. Tennessee court: if we allow mixed-race marriages, next we will have harems in Memphis. Handgun registration leads to confiscation, gay marriage leads to legalizing polygamy, assisted suicide leads to mercy killing. The parade may or may not be plausible; one can always draw the line somewhere. “Taxation is not confiscation while this Court sits.” Distinguish whether the first decision lowers the cost of the second one (registration facilitates confiscation); affects attitudes (9/11 affected attitudes toward surveillance); entails concern for equal treatment (mercy killing); or raises prospect of power abuse (advertising will increase marijuana use).
19. Acoustic Separation. A fancy term for situations where there is a difference between the rule that is publicly announced and the rule that is actually applied. Consider the necessity defense in criminal law, available to sudden decisions but not to booby-traps. When making a snap decision, you won’t be thinking about what the legal rule is, so the legal rule won’t penalize behavior that would be sanctioned if premeditated. The publicly announced strict fiduciary standard isn’t always applied to corporate directors in the absence of self-dealing.
20. Property Rules and Liability Rules. Stemming from a famous Harvard Law Review (!) article by Yale law professor Guido Calabresi & Douglas Melamed. A property rule means a right can’t be invaded without its owner’s consent. A liability rule means a right can be invaded so long as the owner is paid. There are also mixed possibilities (compensatory damages (LR) plus punitive damages (PR); “coming to the nuisance” cases where a plaintiff can win affirmative relief yet still have to compensate the defendant).
21. Baselines. What is normal and what is abnormal? Shelley v Kraemer: racial covenants are private acts, but attempting to use the courts to enforce them was held to be state action. In my subsidy article, I asked what is a general act of regulation, and what is a subsidy. Consider a taking of property vs zoning regulation that substantially prevents a use.
IV. PSYCHOLOGY
22. Endowment Effect. We tend to value what we have, more than what we don’t, even when the things are the same. Willingness to pay WTP, willingness to accept WTA. A ticket we bought for $100 may now be worth $500. Even if you only value it at $100 you still tend to go rather than sell it for $500. If you lose the ticket, you wouldn’t go out and buy another. Costs valued higher than gains. Shows up in valuing property damage or environmental harm.
23. Hindsight Bias. Users of the Learned Hand formula (B < P x L (burden of taking precautions) < (probability of loss if precaution not taken) x (gravity of loss)) from Carroll Towing (2d Cir. 1947) inflate the P, the probability that an accident will occur, because when they are employing the formula, after the fact, the accident DID occur. The rule in Tarasoff of therapist liability, for not warning someone of danger revealed in a therapy session, was resolved in a case after the patient did in fact injure someone. What injuries will happen as a result of that disclosure rule, when troubled people don’t go to therapists in the first place or talk to them openly when they do see them?
24. Framing Effects. A middle position seems reasonable to us. Overton window moves the debate to the middle of a new frame. Prospect theory—people are loss averse. A “cash discount” is perceived as a more attractive price term than a “credit penalty,” even if it is the same policy.
25. Anchoring. Start with one number, no matter how unreasonable, and it is hard to move off of it. Asking a jury for a lot of money has been proven to yield a lot of money—not as much as you ask for, but more than if you had asked for less! An argument for lawmaking by legislatures (and agencies) rather than by courts that get focused on what happened in the case at bar.
26. Self-Serving Bias. If something makes us better off, we are more likely to believe it is present. All of us feel we are above average. We take credit for our successes and blame others for our failures. Thus, we sometimes sanction even successful plaintiffs with the other side’s attorneys’ fees if they turned down a settlement offer that was better than their trial victory.
V. EVIDENTIARY
27. Presumptions. Courts don’t rule that something is true or false, they rule that something is more or less likely than the applicable standard. To do this, they use presumptions, burdens of proof, default rules, principles of deference. Burdens of proof can shift—burden starts with the plaintiff to make out a prima facie case, then shifts to the defendant as to an affirmative defense, etc. Presumptions can differ on appeal between factual findings and legal conclusions.
28. Standards of Proof. 50+ percent preponderance, clear and convincing, beyond a reasonable doubt. Harshness and irreversibility of result associated with the higher burdens.
29. The Product Rule. Don’t forget that a percent of a percent is an even smaller likelihood. Beware of arguments multiplying percentages as if they were independent (10% mustaches x 20% beards) because the variables are often dependent (beards and mustaches frequently go together).
30. The Base Rate. Even if a dog is 99% accurate at identifying drugs, if the base rate is one in a million, the dog will produce many more false positives than correct positives. Work through Bayes’ Theorem. Memorize AB AB AB, then break up as P(A|B)=[(P(A) x P(B|A)]/P(B).
31. Value and Markets. Now consider calculation of damages. What if I subjectively value the lost car more than its market price? How do we compensate for pain and suffering? EPA uses cost-benefit factor of $6 million per loss of life. We take a rather inconsistent approach to using a market to help value benefit and detriment.
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In any event, forearmed with this synthesis, I (and I hope you readers) will return to the nuanced complexities and academic discussion in Farnsworth’s excellent work.
Farnsworth describes it as “the book I would like to have read before I went to law school, [or] when I got out of law school, [or] at various earlier points in my career.” That is the objective for much of my own work—I write what I myself wish I had read a long time ago!