From Anecdata to Data on Writing a Winning Brief

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What is the underlying support for legal writing advice? Much of it, unfortunately, seems to be based on anecdata—a recommendation from a successful litigator, a conversation with a judge at a networking event, or perhaps a horror story from a senior partner. These are all good sources of wisdom, to be sure. I’ve gotten some great advice from conversations with judges and lawyers. But can’t we be a bit more scientific?

Among lawyers and, yes, even law professors, legal writing advice often suffers from a lack of rigor. Each brief, each mediation letter, each reply—these are all one-shot experiments that cannot be tested by the adjustment of variables. If a motion succeeds, then of course the writing must have been brilliant, the use of case law sophisticated, and the structure easy to follow. On the other hand, if a motion fails, well, perhaps the law just wasn’t supportive, or the judge just got it wrong. Who can say if the writing, the structure, or the presentation had a negative effect? It’s difficult to know whether to take writing advice from even the most successful attorneys. Are they successful because of some unique style quirk, or despite that quirk’s tendency to annoy judges?

With that general uncertainty in mind, I was excited to read a recent study from Brian Larson, a professor at Texas A&M University School of Law.11 Brian N. Larson, “Precedent as Rational Persuasion,” 25 Legal Writing: J. Legal Writing Inst. 135 (2021), In the study, Professor Larson set out to examine—rigorously and meticulously—how practicing lawyers and judges actually use case law to support their arguments in briefs and opinions. Sure, plenty of people offer advice on how to present arguments in legal briefs.22 We do a lot of that here in “Write to Counsel”! It’s all good advice. You should check out the archives at But that advice is rarely backed up with hard data about how lawyers and judges write in the real world.

Professor Larson’s study produced some fascinating results that might influence your strategic writing decisions. But to understand those results, I need to tell you a bit about the study. Professor Larson was interested in examining how lawyers and judges use case law to support their written legal arguments. To do that, he started by categorizing different possible uses of case law. Here’s his list:

Stating a Rule – A legal writer might use a case as authority for a direct statement of a legal rule. For example, if you write that an enforceable contract requires consideration, that’s a simple rule statement. Your case citation after that statement would fall under this category.

Providing an Example – Legal writers often reason by analogy to prior precedent. If an author uses the specific facts of a previous case to explain the workings of a legal rule, or to compare the precedent’s facts to her client’s facts, that use would fall under this category.

Offering a Policy Justification – Legal writers understand that broader policy considerations might influence a court’s decision. If a lawyer relies on a case to discuss the policies behind a rule, or if a judge explains that a certain policy supports an outcome, those uses would fall under this category.

Making a Generalization – A legal writer might explain a rule by describing what courts generally do, or routinely do, or traditionally do. For example, if an author uses a case to support her assertion that courts routinely enforce noncompetition restrictions that last less than one year, that use would likely fall under this category.

I can already hear your objections. There are infinite ways in which lawyers and judges use cases to support their arguments! It can’t possibly be true that these four categories of argument cover the field!

Well, you’re right. But you’re probably not as right as you think. Professor Larson examined literally thousands of case references in briefs and opinions. Over 93 percent of those references fell into at least one of these categories. Of course, lawyers use case law for other purposes. One obvious use: attributing quotations. A quotation, however, will almost always be used in service of one of the four previously stated categories of use. But in any event, Professor Larson’s study also separately tracked the use of quotations.

Lastly, the study included a “catch-all” category, which covered the handful of uses that didn’t fit nicely into one of the four main categories. One catch-all use you’ve probably seen a few times: the parting shot! Lawyers love to include a witty quip or nice turn of phrase at the end of an argument section or in a brief’s conclusion. That kind of parting shot might not be a formal logical argument, but it certainly has some rhetorical appeal. Uses like that filled out the remaining 7 percent.

Now things get really interesting. With the categories set, Professor Larson was able to look at how (and how often) lawyers and judges employ these different kinds of arguments. His study was ingenious. First, he collected 199 different pieces of legal writing—55 court opinions and 144 accompanying briefs. To ensure some level of baseline commonality, he chose federal court cases involving copyright’s “fair use” defense. All the opinions and briefs were therefore addressing the same substantive issues. Then, with the help of some research assistants, Professor Larson broke the samples into “argument segments,” with each segment containing a single legal claim.

Armed with his categories of case law “uses,” Professor Larson was then able to examine how the lawyers and judges used case law to support the arguments in each individual segment. Not only that, he was also able to compare argument uses across different types of briefs and different types of legal writers. His findings have some useful and powerful insights for lawyers and judges alike. Without further delay, here you go:

As a baseline, the study found significant differences in how often the different categories of case uses are employed by legal writers. Perhaps not surprisingly, rule statements were the most common type of use. Legal writers used cases to support statements of a legal rule about twice as often as they used cases to advance analogies. And they used analogies about twice as often as they used cases to support policy arguments. So a hierarchy of uses emerged, at least with respect to frequency: rules over analogies, and analogies over policy arguments.

But from that baseline, the study revealed significant differences in how often different types of authors and different types of briefs employed the various case uses. For example, judges and lawyers both used rule-based arguments more than example-based arguments. But between the two groups, judges tended to use rule statements more than lawyers, who tended to use examples and analogies more than judges. Both types of writing were rule heavy, to be clear; judicial writing was just more rule heavy. As a lawyer, therefore, you might not want to mimic judicial writing’s paucity of examples and analogies, since that style does not reflect advocates’ greater use of those arguments.

Perhaps most importantly, Professor Larson found differences between winning and losing briefs. Across the board, winning briefs simply used more cases and offered more arguments. Does that mean you should pad your briefs with additional irrelevant case citations to increase your chances of winning? Probably not. The study didn’t prove causation. And it’s entirely possible, of course, that winning briefs use more cases simply because more case law exists to support a winning position. It’s not the losing lawyer’s fault that he’s stuck with less favorable precedent to work with.33 But as I’ve previously argued in this column, lawyers should still use “bad” cases. See David J.S. Ziff, “There’s No Such Thing as a ‘Bad’ Case,” Wash. State Bar News, July-Aug. 2019, at 17-19,

But I don’t think the amount of case law tells the whole story. The winning briefs didn’t just use more cases to make more arguments; within those arguments, the winning briefs emphasized different kinds of arguments. Winning briefs really outpaced the losing briefs in three categories: the use of quotations, the use of examples and analogies, and the use of policy arguments. Yes, winning briefs also used slightly more rule-based arguments. But that difference was not as pronounced as the more sophisticated and subtle work of presenting analogies, advancing policies, and selecting quotations.

Obviously, all of this should be taken with a grain of salt. Professor Larson’s study is but one look at a small set of federal district court copyright disputes. And though the study was sufficiently robust to show real differences, we can’t yet make any confident statements about causation.

But still, it’s wonderful to have real data on which to base some writing recommendations. Personally, despite all the cautionary notes, I would recommend making sure that your next brief effectively uses some examples and analogies, presents some policy arguments based in case law, and artfully employs some selected quotations. After all, it can’t hurt to at least look like a winning brief! 

About the author
About the author

David J.S. Ziff is an associate teaching professor at the University of Washington School of Law. You can follow him on Twitter at @djsziff.
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1.  Brian N. Larson, “Precedent as Rational Persuasion,” 25 Legal Writing: J. Legal Writing Inst. 135 (2021),

2.  We do a lot of that here in “Write to Counsel”! It’s all good advice. You should check out the archives at

3.  But as I’ve previously argued in this column, lawyers should still use “bad” cases. See David J.S. Ziff, “There’s No Such Thing as a ‘Bad’ Case,” Wash. State Bar News, July-Aug. 2019, at 17-19,