A statistical review of the 2021-2022 Iowa Supreme Court term: while polarization recedes, disagreement persists

by Iowa Appeals Blog | October 27, 2022

[This article by Matthew A. McGuire and Spencer S. Cady was originally published in the August 2022 issue of The Iowa Lawyer magazine. The 2021-2022 term statistics were compiled by Chris Slack.]

The 2021-2022 term of the Iowa Supreme Court concluded on June 30. A statistical analysis reveals that the recent trend of reduced polarization among the current justices in non-unanimous cases continues, with the justices deciding fewer closely divided 4-3 cases. The data also shows continued independence among the individual justices, with the justices agreeing or disagreeing with one another in a much less predictable fashion from case to case—a contrast from the durable 3-3-1 alignment of the previous Cady Court.

But reduced polarization in alignment among the justices in close cases has not heralded an era of consensus. In fact, the opposite is true. In deciding 105 cases this term, the justices issued 72 separate opinions concurring with or dissenting from the majority opinion—and often both at once. This is a marked increase in disagreement compared with prior terms. So, while the number of closely divided cases has dropped, it appears there remain many topics about which the justices disagree.

Opinions by the numbers

The Iowa Supreme Court decided 105 cases by opinion last term, which is consistent with historical opinion totals, but a decline from last year’s 119 cases decided by opinion. Sixty-six of these opinions were unanimous, while 39 were non-unanimous. As noted above, in those 39 non-unanimous cases, individual justices authored 72 separate opinions concurring with or dissenting from the majority opinion. This is a notable increase of approximately 25% compared with prior terms. Between the 2017-2018 term and the 2020-2021 term, the justices collectively issued on average only 58 separate opinions.

By contrast, the number of closely divided opinions—cases decided on a 4-3 or 4-2 basis—has steadily declined. This year’s 15 closely divided opinions represented a modest increase over last year’s 11, but the court averaged 20 closely divided opinions between the 2017-2018 term and the 2019-2020 term. In other words, while the justices were less likely to disagree with one another this term compared to previous terms, if they did disagree, they were more likely to write about why.

Separate opinions and closely divided cases

This term, 43 cases came to the court by way of direct appeal, while jurisdiction in 52 cases arose as a result of further review of the Iowa Court of Appeals. These two categories comprised 90% of the total cases. The court heard four cases on direct interlocutory appeal and six attorney discipline cases. These proportions are consistent with prior terms.

This term also continued the Iowa Court of Appeals’ recent streak of success when reviewed by the Iowa Supreme Court. Similar to last term, the Iowa Supreme Court affirmed the Iowa Court of Appeals on 42% of cases, reversed on 42% of cases and rendered a mixed opinion affirming in part and reversing in part in 15% of cases. While 42% may not seem to be a high affirmance rate, it easily tops the Iowa Court of Appeals’ affirmance rate of 20-30% during the latter half of the 2010s.

Reversal rates: Court of Appeals

Justice Appel, in his final term on the court, continued his years-long streak as the most prolific justice, authoring the most opinions with 35, including 10 concurring opinions and 14 dissenting opinions. Justice McDermott authored 30 opinions, including five concurring opinions and 12 dissenting opinions. Chief Justice Christensen and Justice Oxley authored a combined five separate opinions, tending to join the opinions of their colleagues when concurring or in dissent rather than offering their own separate opinions.

Total opinion authorship

Frequency of agreement

Most of the court’s opinions this term were unanimous. Keeping with the theme of this term, however, it was a somewhat lower percentage than usual. Of the court’s 105 written opinions, 66 were unanimous—or about 63% of opinions.

For non-unanimous cases, this term continued the recent trend of shifting and unstable alignments between justices from non-unanimous case to non-unanimous case. While in prior terms multiple sets of justices found themselves in agreement on over 90% of non-unanimous cases, there was no such combination this term. Justice Waterman and Justice Mansfield again agreed with each other more frequently than any other pair of justices, but even these two justices were in agreement in only 78% of non-unanimous cases, down from 91% last term. This represents the lowest high-water mark in any recent term.

Instead, almost every justice agreed with every other justice between 30-70% of the time. Justice Appel and Justice McDermott in particular exhibited the narrowest range, neither agreeing nor disagreeing with any particular colleague on a consistent basis.

Agreement Among Justices: Non-Unanimous Opinions

Justice alignments in 4-3 opinions

The 2021-2022 term featured 15 closely divided cases, or cases decided on a 4-3 or 4-2 basis. Interestingly, the justices least likely to be in the majority in closely divided opinions last term – Chief Justice Christensen and Justice Appel – were the most likely to be in the majority on closely divided opinions this term. While Justice Appel authored the most separate opinions and the most dissents overall and was the least likely justice to agree with his colleagues in divided opinions, the data shows that most of these disagreements arose in the context of 6-1 or 5-2 opinions where Justice Appel dissented. Justice Appel was in the majority for 11 of the court’s 15 closely divided opinions.

Justice McDermott was least likely to be in the majority this term, dissenting in 10 of the 15 closely divided cases. And while last term Justice Waterman and Justice Mansfield found themselves in the majority of closely divided cases over 80-70% of the time, respectively, this term these justices were far less likely to join the opinion of the court in such cases – only 53% of the time for Justice Waterman and 43% of the time for Justice Mansfield.

Once again, there was no consistent voting “bloc” of justices in these closely divided cases. The most frequent alignment of justices consisted of Justices Appel, McDonald, Oxley and McDermott, constituting the majority of the court in four of the 15 closely divided cases. This alignment prevailed in only two closely divided cases last term. By contrast, last term’s most frequent alignment – Justices Waterman, Mansfield, McDonald and Oxley – never arose this term.


After a period during which four seats on the Iowa Supreme Court turned over during a span of just a few years, the Iowa Supreme Court’s 2021-2022 term marked the second full term with the then-existing composition of justices. Within this sample size, the most striking statistical takeaway remains the end of clear patterns of agreement or disagreement between individual justices in non-unanimous cases. (And, perhaps, that opinions of the Court of Appeals are considerably more likely to be affirmed.)

With Justice Appel’s retirement at the end of the 2021-2022 term, the Iowa Supreme Court’s composition will change once more. It may, therefore, become even more difficult for practitioners before the court to predict which justices will agree with one another from case to case.

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