As we all await the next administrative law earthquake from the Supreme Court, it may be worth taking stock of just how much the ground has already shifted. In our new article, Major Rules in the Courts: An Empirical Study of Challenges to Federal Agencies’ Major Rules, we provide this analysis. Using a novel dataset of all 1,870 major rules (as defined by the Congressional Review Act) issued from 1996 through the end of the Trump Administration, we analyze whether a major rule issued today is as likely to be challenged and withstand the challenge as a rule issued over 20 years ago. In addition to answering those overarching questions, we break down win rates by presidential administration and agency, as well as by party of the deciding judges’ appointing President. Along the way, we examine trends in forum shopping and the use of Chevron deference, among other variables.

Our study differs from past studies of agency win rates in two important respects:

First, rather than constructing our dataset from opinions resolving legal challenges to agency actions, we begin with the universe of major rules and then determine which ones were ultimately challenged. This feature allows us to examine an often-overlooked question: How many major rules go unchallenged. (The answer, as it turns out, is a lot.)

Second, our study covers what we understand to be the longest continuous timeframe of any analysis of agency win rates. Beginning with the passage of the Congressional Review Act in 1996, our universe of rulemakings spans roughly 24 years and captures the major rules of four presidential administrations (two from each party), allowing us to conduct a big-picture analysis of how administrative law and agency success have changed over time. Our preliminary analysis of the Biden Administration’s major rules offers additional years of analysis.

So, what did we find? Let’s start with the challenge rate to agencies’ major rulemakings. Of the 1,870 major rules in our dataset, only 397 (slightly over 20%) were challenged. But that challenge rate has increased over time, rising from slightly under 17% for Clinton Administration major rules to just over 28% of Trump Administration major rules. The challenge rate also varied greatly by issuing agency. For example, the Department of Health and Human Services, which issued far more major rules than any of its peer agencies, saw 18% of its major rules challenged; for the Environmental Protection Agency, the figure was 76%.

Similarly, we saw substantial variation in win rates—sometimes referred to as “validation rates”—across time and agency. Of the 320 challenged major rules addressed in at least one judicial opinion, 49% entirely withstood judicial scrutiny. That rate varied by administration: 63% for the Clinton Administration and 31% for the Trump Administration, with the W. Bush and Obama Administrations landing in between (but closer to the top of the range). Early analysis of the Biden Administration’s rules suggests that, while agency win rates have increased since the previous administration, they have not returned to their earlier highs.

Some agencies won more frequently than others: Federal Communications Commission rules fully withstood challenge almost three-quarters of the time while Environmental Protection Agency rules fully withstood challenge only 36% of the time. That said, the Environmental Protection Agency also saw the highest percentage of mixed results, meaning either that a single court found some but not all challenged provisions invalid or that different courts reached different conclusions over the same major rule. Weighing those mixed results changes the picture for EPA, especially if one includes mixed results that led only to a remand without vacatur. Taking that latter approach, EPA’s win rate rises to just over 62%. This example demonstrates that there is much nuance in our data, which we try to present so that readers, who may view the data very differently, can reach their own conclusions.

Perhaps surprisingly given the tenor of recent debates concerning the administrative state, judges appointed by Republican Presidents upheld major rules just as frequently as judges appointed by Democratic Presidents. But H.W. Bush and Clinton appointees were more likely to side with an agency than Obama and Trump appointees.

Other findings of note include an increase in forum shopping, potentially diluting the historic dominance of the D.C. Circuit in matters of administrative law. While over half of all challenges to Clinton Administration major rules were filed in the D.C. Circuit, only 12% of all challenges to Trump Administration major rules began there. The trend has continued during the Biden Administration: Almost 40% of challenges to the Administration’s major rules began in the Fifth Circuit or one of its district courts. We are also seeing more challenges per major rule; while only 10% of challenged W. Bush major rules saw litigation in more than one federal court, 33% of Trump’s challenged major rules were subject to such multi-venue litigation.

Our article contains much more analysis than can fit in one blog post, in addition to a detailed account of our methodology and various caveats and study limitations. We are also releasing the dataset underlying our analysis in the hope that it will prove useful to other administrative law scholars. (We invite them to flag any errors they spot in our dataset or coding.) Ultimately, we view this living dataset as a starting point, not an end, to the discussion.

Libby Dimenstein is a law clerk on the U.S. Court of Appeals for the Third Circuit; Don Goodson is the Deputy Director of the Institute for Policy Integrity at NYU School of Law; and Tyler Szeto is an attorney at Earthjustice. Both Dimenstein and Szeto began work on this study and article when they were Legal Fellows at Policy Integrity.