The Yale Law Journal


Dictionaries 2.0: Exploring the Gap Between the Supreme Court and Courts of Appeals

14 Sep 2015
James J. Brudney & Lawrence Baum


The remarkable rise in dictionary usage by the Supreme Court since the mid-1980s has been a subject of considerable scholarly and media interest. We published an article in November 2013 that explored the Court’s new dictionary culture in depth from empirical and doctrinal perspectives.1 In a Yale Law Journal Note one year later, John Calhoun embraced some of our findings, criticized others, and—importantly—broadened the inquiry to identify a sizeable gap in overall frequency of citation to dictionaries between the Supreme Court and the federal courts of appeals.2

This gap in dictionary usage is our primary focus here. Previously we analyzed nearly 700 Supreme Court cases decided between 1986 and 2011, taken from three fields that together comprise substantial portions of the Court’s statutory docket: labor and employment law; business and commercial law; and criminal law.3 In this Essay, we examine dictionary use by federal courts of appeals in these same cases before the Supreme Court granted certiorari and reviewed them. Our analysis encompasses majority opinions from the circuit courts in 109 cases where the Supreme Court subsequently made affirmative use of dictionaries and in 106 cases where the Court’s decisions did not make use of dictionary definitions.4

We find that circuit courts cited to dictionaries in only one-sixth of the cases where the Supreme Court went on to use dictionaries after granting certiorari and in only about one of every nineteen cases in which the Court did not use dictionaries. The frequency of circuit court citation increased from the early Rehnquist Court period to the late Rehnquist and early Roberts Court years, but over that same period the gap between appeals court and Supreme Court references to dictionaries grew by substantial amounts. Further, when dictionary definitions were invoked, Supreme Court justices relied on those definitions to help justify the result (not simply as citations in dicta) over four-fifths of the time—twice as often as circuit court judges did when they cited dictionaries. Additional findings, reported below, support our conclusion that there are striking differences between the dictionary cultures in the Supreme Court and the courts of appeals.

We begin by setting forth brief background regarding how our approach to analysis of dictionary use differs from Calhoun’s. Contrary to Calhoun’s assertions, there are no direct disagreements between us when our respective Supreme Court datasets are properly compared.5 We then describe our empirical approach to the courts of appeals data and present our findings, which relate to the basic gap in frequency of usage and reliance. We also describe some finer-grained observations regarding number and types of dictionaries used, and how often the circuit court judges and the justices define the same word in the same case. Finally, we suggest possible reasons why the Supreme Court uses and relies on dictionaries so much more often than circuit courts, and we outline plans for further research in this area.

I. clarifying issues in supreme court dictionary practices

A. Background and Previous Research

Calhoun frames his Supreme Court inquiry largely in relation to our own research on dictionary use.6 Our article was an effort to combine breadth and depth in analysis of dictionary use in the Supreme Court. We focused on opinions for the Court while giving secondary attention to dissenting opinions in cases in which majority opinions used dictionaries. We analyzed overall frequencies of majority opinion use in three prominent statutory fields over time. We compared dictionary use across justices (and groups of justices classified by ideological position); examined patterns in the numbers, kinds, and publication dates of dictionaries used; and compared justices’ use of dictionaries with use in the briefs in the same cases. We then looked more closely in doctrinal terms at the ways that justices employed dictionaries as bases for their conclusions about the meaning of statutes.

Calhoun provides a different perspective by emphasizing breadth over depth. The sole concern of his empirical inquiry is whether or not an opinion cites any dictionaries, and he breaks down dictionary use only by justice and ideological groups of justices. Rather than limiting himself to opinions for the Court, or to certain statutory fields, he examines all opinions in all cases.7 Thus his inquiry overlaps with one part of what we did.

B. Clarifications in Response to Calhoun

Calhoun argues that we are mistaken on certain empirical matters. To address those critiques, we first need to consider differences between his set of Supreme Court opinions and ours. One difference is clear: Calhoun’s data are not limited by legal area. Beyond this, his criteria are not entirely clear. He seems to include both non-statutory cases and statutory cases that fall within the time period of his study,8 and he takes concurring and dissenting opinions into account even when they do not accompany a majority opinion citing to a dictionary.9 Calhoun appears to combine those separate opinions with majority opinions in analyzing the percentages of cases in which the Court cited to dictionaries.10 It also appears, though this is less clear, that in addressing the frequency of dictionary citation by different justices, he analyzes both separate and majority opinions by each justice.11 Because our primary analyses were limited to majority opinions, and more than ninety-five percent of the cases in our sample were statutory, our analyses and those done by Calhoun are not fully comparable. So we proceed with caution.

Two of the matters on which Calhoun perceives disagreement between his findings and ours are of some importance.12 One concerns the timing of the growth in dictionary use. We accepted growth before and during the early 1980s as a given, based on the findings of other scholars.13 We then described the increase that occurred in our dataset majority opinions from 1986-91, and the further growth that occurred during the 1990s and 2000s.14 Calhoun argues that the sharpest increase in dictionary citation occurred in the late 1980s,15 while we gave more emphasis to the growth in the early 1990s.16

Contrary to Calhoun’s Note, we did not offer any conclusions about when the Court’s increase in dictionary usage became “precipitous.”17 We did note that although Justice Scalia authored an exceptionally large number of separate opinions using dictionaries between 1986 and 1991, the Court’s reliance on dictionaries in majority opinions in our dataset grew more substantially after 1991 than it had between the early 1980s and the 1986-91 period.18 The data Calhoun presents are not altogether clear on the timing of growth in dictionary use when compared to our findings, because his data are aggregated by decade. His somewhat different base of Supreme Court opinions—including dissents and concurrences—also provides a different vantage point on the growth, but there is no direct disagreement between him and us.

The other matter of perceived disagreement concerns ideology and dictionary use. We found no meaningful difference between liberal and conservative justices with respect to the frequency of dictionary use in opinions for the Court.19 We also found, however, that conservative justices were significantly more likely to use dictionaries in dissenting opinions.20 Calhoun finds a higher rate of dictionary use by conservative justices and concludes that our findings were incorrect.21 He does not test for the statistical significance of the difference between conservatives and liberals, but it appears that in some periods the difference between them is large enough to be significant. At the same time, if Calhoun included dissenting and concurring opinions in his analyses of dictionary usage by individual justices, as he seems to have done, his findings are consistent with our finding of similarity between liberals and conservatives in majority opinions and a sharp difference between them in dissenting opinions.

In sum, we and Calhoun do not actually disagree on the timing in growth of Supreme Court dictionary use. Moreover, his perception of the differences between his and our findings on ideology and dictionary use appears to rest on his aggregation of majority and dissenting opinions that we analyzed separately. His findings on use of dictionaries in the Supreme Court are helpful because they corroborate and extend the findings of prior studies, not because they refute those findings.

Calhoun’s more important contribution to the dictionaries debate involves his threshold finding of comparatively low citation rates in the courts of appeals. He reports that the overall rate of dictionary citations “slightly increased” from two percent of all decisions in 1950 to seven percent in 2010.22 An increase by a factor of around three and a half might not be viewed as “slight” in some settings, but as Calhoun observes, the increase is quite modest compared to what has occurred in the Supreme Court during the same period, and especially in the past three decades. As a result, the overall rate of dictionary use in the Supreme Court has become far higher than the rate in the courts of appeals.

We were intrigued by Calhoun’s circuit court findings and decided to explore the divergence between Supreme Court and court of appeals usage in more depth while retaining a degree of breadth as well. By gathering data on circuit court dictionary usage for 215 cases in which we previously analyzed dictionary use (or lack thereof) in the Supreme Court, we are able to probe differences in approach between these two judicial levels by comparing dictionary use in the same cases.

II. divergent dictionary practices in the courts of appeals

A. Our Empirical Approach

Our analysis was based on two sets of cases involving both a Supreme Court and a circuit court decision. One set consists of all cases in our original Supreme Court dataset in which the Court’s majority opinion used a dictionary, so long as the case came from a federal court of appeals that had issued an opinion. The second set is comprised of a one-fifth sample of the cases in our original dataset in which the Court’s majority opinion did not use a dictionary, so long as the same two criteria were met.23 This sample was stratified so that the proportions of cases in the three statutory fields and from different time periods matched the proportions in the full set of Supreme Court cases not using a dictionary. Most of our analyses include both sets of cases, and in those analyses we weighted cases in the second set so that their proportion was the same as it was in the original dataset. Altogether, our analyses included 215 cases or, with weighting, 639 cases.24 Our procedure to identify dictionary use by courts of appeals in the selected cases involved a search for words or word fragments related to such use, followed by reading of opinions to determine whether a dictionary actually was cited.25 In both the Supreme Court and the courts of appeals, we focus on majority opinions.26

B. Findings on Frequency of Dictionary Usage

Altogether, Supreme Court majority opinions used dictionary definitions in 17.1% of the cases, compared with 7.2% for the courts of appeals.27 Table 1 shows the relationship between use of a dictionary by the Supreme Court and use by the court of appeals deciding the same case. As the table indicates, courts of appeals were considerably more likely to use a dictionary in cases in which the Supreme Court subsequently did so than in other cases. That relationship may stem from attributes of cases that make dictionary use seem more appropriate, from the influence of dictionary citation by the court of appeals on the Supreme Court, or a combination of the two.


Importantly, these findings also show that for cases in which the Supreme Court used a dictionary, the court of appeals had done so only about one-sixth of the time. The Supreme Court’s dictionary use may relate to its reason for granting certiorari on statutory questions, which in recent decades is typically in order to resolve a conflict in the circuits or between a court of appeals and a state court of last resort.28 Such conflicts invite the justices to undertake first-order inquiry into what has become the highly contested meaning of certain statutory text. At the same time, a statutory case on which certiorari is granted has either created or crystallized the circuit court conflict; it seems probable that the parties and/or the judicial law clerks have made the appellate court panel aware of this conflict prior to its decision. Yet court of appeals judges are much less likely than Supreme Court justices to invoke dictionary definitions when faced with these conflicting approaches to an issue of statutory interpretation.

Admittedly, there are instances when the circuit courts used a dictionary and the Supreme Court did not do so after granting certiorari in the same case. But these instances amount to a very small proportion of Supreme Court non-use cases, about one in nineteen. They do not detract from our essential finding that, when reviewing the same legal and factual controversy, the justices are far more inclined to deem dictionary definitions worthy of consultation than are their appeals court counterparts.

Temporal patterns are shown in Table 2. The table can be interpreted in two different ways, depending on the measure applied. Dictionary use by the Supreme Court was double that in the courts of appeals in 1986-91, and the same ratio existed in 2005-2010. In that sense, the relationship between the two levels remained stable (though the ratio was higher in between those two periods). But this stability meant that the gap in the frequency of dictionary use between the two courts grew quite considerably, from 3.5 percentage points in 1986-91 to 14.1 percentage points in 2005-2010. Thus, even when we control for the content of cases, there has been a very substantial—and growing—difference in dictionary use between the Supreme Court and the courts of appeals.2930


C. Other Patterns in Dictionary Usage

We can gain a fuller sense of the comparison between the two levels of courts by considering other attributes of their dictionary usage. In this regard, there is a difference between citing a dictionary definition and actually relying on that definition as a basis for decision. In our earlier article, we gave special attention in doctrinal terms to instances where the Court used dictionaries to explain or justify its holding. Analyzing numerous case law examples, we explained how the Court relied on dictionaries in this manner either by contributing to a result reached primarily on other interpretive grounds (which we called ornamental use of dictionaries) or by helping to establish a result with such clarity that other resources, especially deference to administrative agencies and use of legislative history, were essentially ignored (which we called using dictionaries as a barrier).31

In the dataset for this Essay, 81.7% of the 109 Supreme Court majorities that invoked dictionary definitions relied on these definitions rather than merely citing to them in dicta or deflecting them as inconclusive or inapposite. By contrast, only 40.8% of the circuit court references to dictionary definitions involve actual reliance; almost three-fifths reflect background citation or some form of deflection.32 Thus, not only does the Supreme Court cite dictionaries far more often than the courts of appeals, but it is also twice as likely to rely on one or more definitions that it cites than are the courts of appeals. Put differently, the gap between the two levels in the importance of dictionary definitions to decisions is even greater than the frequency of citations to dictionaries suggests.

The balance between general dictionaries (such as the various “Webster’s” dictionaries, the Oxford English Dictionary, and the American Heritage Dictionary) and legal and technical dictionaries (primarily Black’s Law Dictionary) was about the same at the two levels—sixty-six percent general dictionaries in the Supreme Court, sixty-two percent in the courts of appeals. The two levels were also similar in the frequency with which they cited more than one dictionary definition for the word or phrase in question—thirty-seven percent in the Supreme Court, thirty-one percent in the courts of appeals.

One issue we discussed in our earlier article was the relationship between dictionary use by the Supreme Court and by briefs for the parties (or the federal government as amicus). We found a conspicuous divergence between the words for which the briefs used dictionaries and the words for which the Court’s majority opinion did so.33 Here, we explored the same questions in an analogous way, comparing the words for which the circuit courts used dictionaries with the words for which the Court’s majority opinion did so in the same case. To start with, in the great majority of cases in which one or more dictionaries were cited at either level (eighty-three percent of the time), no dictionaries were cited at the other.34 The fact that these two levels of appellate tribunals cannot even agree on whether any statutory terms require reference to dictionaries lends support to our earlier conclusion that the dictionary as an interpretive resource is being used in strikingly subjective ways.35 Moreover, in the cases in which both the Supreme Court and the court of appeals used dictionaries, only thirty-three percent of the words defined by one were also defined by the other.36 This finding further reinforces the implication of our prior analyses, where we concluded that dictionary use by the Supreme Court is “more casual and arbitrary than principled or systematic.”37

In sum,there are deep and continuing differences in how Supreme Court justices and circuit court judges have approached dictionary usage over a twenty-five year period. We turn next to possible explanations for those differences.

III. accounting for the gap

Our most notable findings involve disparities in frequency and depth of usage by courts of appeals and the Supreme Court. Although Calhoun identified this phenomenon in broad terms based on dictionary citations, our analysis of the identical set of cases from circuit courts and Supreme Court establishes the magnitude and nature of the gap in a context that is more focused and fine-grained.

Normative and empirical research on the use of various interpretive resources has long concentrated on the Supreme Court. More recently, some scholars have argued as a normative matter that interpretive approaches should not be uniform across the judiciary, given salient political or hierarchical differences between the Supreme Court and lower federal courts, or between federal appointed and state elected judges.38 For example, with respect to the hierarchy of federal courts Aaron-Andrew Bruhl suggests that because Congress is unlikely to monitor or be aware of lower federal court decisions, interpretive doctrines such as valuing congressional acquiescence or crediting the disciplining effects of strict textualism may have no relevance in lower court settings.39 Empirical studies of circuit court interpretive approaches in more recent decades have produced interesting though inconclusive results regarding use of particular resources such as legislative history and canons.40

Our findings, based on decisions by two levels of the federal judiciary in the same cases, invite reflection as to what accounts for such dramatic interpretive divergence in dictionary usage between these two different levels. We propose that hierarchical differences in decision-making processes and institutional structure between the Supreme Court and the courts of appeals play a central role in accounting for the divergence.

A. Political Visibility and Exposure

In our earlier article, we offered a general and a more particularized explanation for the enormous increase in dictionary usage by the Supreme Court. At a general level, we suggested that dictionary use had become an oasis from which the justices sought to deflect charges of judicial activism. We contended that by citing dictionary definitions as linguistic authority for their conclusions about the meaning of statutory text, the justices subtly analogize dictionaries to legal authority and thereby seek to avoid being perceived as acting on the basis of ideology or untrammeled judicial discretion.41 We also noted the especially large increase in dictionary use for criminal law cases. We suggested as an explanation that the justices were emphasizing ordinary meaning and clear notice in a field where defendants often are disadvantaged in terms of both education and resources for securing counsel, and where the stakes in court are exceptionally high.42

Calhoun speculates that our “oasis” explanation may have less resonance in the circuit courts, where judges are less well known, decisions are less carefully scrutinized for activism, and the public inadequately understands circuit court power and influence.43 We agree with him up to a point. However, we found the “oasis” justification itself unsatisfactory in normative terms, concluding that it too often allows or encourages the justices to cherry-pick definitions under the guise of objectivity, and to rely on those definitions to foreclose consideration of highly relevant interpretive evidence from the enacting Congress and the implementing agency.44 It may be that circuit court judges—relatively unaffected by the judicial activism critique—are more sensitive to or cautious about these risks of subjectivity and bias, and therefore less susceptible to being seduced by visions of an oasis.45 Relatedly, several prominent circuit court judges have criticized the acontextual approach that dictionary use by courts tends to reflect if not promote.46

Our particularized explanation regarding criminal law does not appear to resonate in the courts of appeals. Within the cases in our current analysis, the Supreme Court used dictionaries at a twenty-five percent rate in criminal cases, compared with seventeen percent for commercial cases and twelve percent for labor and employment cases. In contrast, the rate of dictionary use in the courts of appeals varied little by field, and it was actually lowest in criminal cases (six percent, compared with eight percent in the two other fields). Perhaps because circuit courts review far more criminal appeals, including a large number that are routine and/or essentially fact-bound, these appeals are less often subject to close interpretive scrutiny. Appeals court judges accordingly may not view the universe of criminal statutory decisions as occasions for establishing broader commitments to the value of clear notice or the importance of ordinary meaning in text.

B. Decision-Making Processes and Institutional Structure

The explanation we offer with respect to criminal law cases suggests how hierarchical differences in institutional structure may play a meaningful role in accounting for the divergence on dictionary use. More broadly, the Supreme Court consists of nine continuous repeat players: they decide all cases together, and over the past few decades there have been several periods of five or more terms—in one instance, eleven terms—with no changes in the Court’s membership.47 When one or two justices begin to invoke dictionaries on a regular basis, the subtle pressure on fellow justices to participate seems real. Whether out of simple respect for colleagues they interact with on 70 to 150 argued cases every Term,48 or from a strategic need to retain members of a majority coalition, the justices appear relatively amenable to incorporating a new interpretive resource into their reasoning framework.49

By contrast, circuit courts lack anything close to the one-hundred percent repeat player element. Even for a smaller circuit, judges sit together only on a very small proportion of all cases.50 The presence of numerous senior status judges on the circuit courts leads to further dilution of repeat player possibilities.51 Accordingly, the idea of a collegial or institutional culture regarding use of particular interpretive resources seems less likely to develop.

A related hierarchical factor is that the Supreme Court’s acceptance of a case means new law will be made. Indeed, as noted earlier, the existence of circuit court disagreement on an issue of statutory meaning is the primary gateway to Supreme Court review.52 And while the justices regularly cite precedent as a mantle of authority in disputes over statutory meaning,53 the Court is seeking to resolve unaddressed problems, which means proceeding largely on an ab initio or de novo analytic basis starting with close textual analysis. Again by contrast, circuit court judges may be less disposed to view disputes on automatic appeal as presenting novel, or important and unresolved, matters of law. By relying more heavily on precedent (their own and the Court’s), they have less occasion to begin from scratch with an analysis that invokes the need to unearth or create fresh ordinary meaning.

This behavioral predilection is especially likely to apply for the first or second circuit court that addresses a statutory issue, when a conflict has not yet arisen. But even appeals court judges who create or sharpen a circuit conflict do not know whether the Supreme Court will grant certiorari to make new law. Their focus in the midst of a heavy mandatory docket is primarily on resolving disputes presented by the parties before them rather than fashioning novel interpretive or doctrinal approaches.

In short, the routinized aspects of circuit court review, encompassing a substantial number of cases that turn on facts alone or on well-settled precedent,54 may contribute to the overall disparity in dictionary use between circuit courts and Supreme Court, as found by Calhoun. But even when circuit court cases raise sufficiently important and unsettled issues to be deemed “cert-worthy”—which is the focus of our dataset—the courts of appeals seem substantially less conditioned to pursue dictionary-based analysis.

By emphasizing the intensely collegial and predictably selective nature of Supreme Court review when compared with circuit court decision making, we do not mean to negate the influence of the Court’s special political visibility and the justices’ likely sensitivity to that role. It is doubtless true that multiple factors help to account for the difference in dictionary usage, especially given its magnitude. For this reason, the explanation we have outlined here is surely incomplete. At the same time, we are persuaded that other differences between the Supreme Court and the courts of appeals—related to dynamics of collegial decision making and comparative aspects of jurisdiction more than to political vulnerability—play an important role in accounting for the striking difference in the use of dictionaries that we and Calhoun have documented. Moreover, because our analysis focused on the same cases in the two levels of courts, we have established that the difference in dictionary use goes well beyond being a reflection of differences in the universe of cases decided by the Supreme Court and the courts of appeals.55

IV. directions for future research

We have analyzed patterns in the use of dictionaries in the Supreme Court and the federal courts of appeals and offered possible explanations for the substantial difference in use and reliance on dictionaries at the two levels. More can be done to explore this difference and its sources. That is especially true in the current era, when dictionaries have become a highly visible and also controversial resource for judges who seek to interpret statutes.

We plan to explore dictionary use more deeply by comparing the Roberts Court from 2005 through 2015 with several federal circuits during the same period. Review of comparative decision making over the full decade will allow us to determine whether the gap between the Supreme Court and the courts of appeals has become stable or continues to grow. Close examination of multiple circuits also will tell us more about similarities and differences among them in dictionary use.

In addition, we can gain a broader perspective by comparing dictionary use with circuit courts’ approach to other important interpretive resources. It might be that courts of appeals make less use of the full range of resources available to them because of differences in styles of opinions or approaches to the task of statutory interpretation. We expect to focus on legislative history, a quite different resource but one that also has been the subject of considerable controversy associated with substantial changes in Supreme Court usage. By comparing circuit court use of dictionary definitions and legislative history, we hope to develop a more complete sense as to the roots of the substantial differences in dictionary use between the Supreme Court and courts of appeals, differences that Calhoun identified and that we have examined more deeply in this Essay.

James J. Brudney is a Professor of Law at Fordham Law School. Lawrence Baum is a Professor Emeritus of Political Science at the Ohio State University. The authors are grateful to Amanda Shami for superb research assistance, and to Fordham Law School for generous financial support.

Preferred Citation: James J. Brudney & Lawrence Baum, Dictionaries 2.0: Exploring the Gap Between the Supreme Court and Courts of Appeals, 125 Yale L.J. F. 104 (2015),