Running Unopposed
Generally, about half of lower appellate court judges run unopposed: In the 2006 election in Ohio, for example, 15 out of 25 candidates featured only one candidate; in 2008, the ratio was 10 of 19; in 2010, the ratio was 7 out of 16. Overall, for the three-election cycle, 53% of the lower appellate judges ran unopposed.

State Supreme Court elections also have a high percentage of unopposed contests. In a study of all state Supreme Court elections from 1986-2006, the percentage of races in which the incumbents faced a challenger varied from 36% to just under 80%. In 2006, the rate of challenges to incumbency was almost exactly 50%.

Percent of unopposed Supreme Court races

1986	1988	1990	1992	1994	1996	1998	2000	2002	2004	2006
64%	45%	47%	41%	37%	23%	21%	25%	32%	30%	50%

The high rate of unopposed races for lower appellate court elections is not too surprising—many of the circuits where these courts are located are essentially one-party circuits, where either Republicans or Democrats dominate to such an extent that there would be no point in running against the dominant party. But the lack of challengers for Supreme Court seats is somewhat curious. Unlike localized appellate court circuits (which are more analogous to state legislative races or federal Congressional races), a Supreme Court election is statewide—yet still around a third of those elections are unopposed. It is hard to imagine any other statewide race—such as a race for Senator or Governor—in which a candidate would run unopposed.

Incumbency advantage—Lower appellate courts
In the lower appellate courts, incumbents so rarely face a challenger that it is hard to get meaningful numbers about how often incumbents win contested elections. For example, here is data from Ohio’s intermediate courts of appeal for the past four elections:

Year	2002	2004	2006	2008	Total
# of incumbents running	13	13	16	13	53
# of incumbents running unopposed	7	19	13	10	40
# of incumbents losing	1	0	1	0	2
% of incumbents losing	8% (1 of 13)	0 of 13	6% (1 of 16)	0 of 13	3% (2 of 53)
% of contested incumbents losing	14% (1 of 6)	0 of 3	33% (1 of 3)	0 of 3	13% (2 of 15)

A study of judicial elections in Wisconsin from 1998 to 2005 showed a similar result: out of 25 appellate court judges who stood for re-election as incumbents during that period, only two of them were opposed, and one of the opposed judges was defeated by his challenger.

Incumbency advantage—Supreme courts
The incumbency advantage for Supreme Court elections is also significant. From 1980 to 1994, approximately 25% of Supreme Court Justices who faced a challenge ended up losing their seat. (Of course, about half of the Supreme Court Justices during this period did not face any opponent at all, so overall the re-election rate for incumbents for this period was 13%). Thus, if a Supreme Court justice is running for re-election and faces an opponent, he or she has about a 1 in 4 chance of losing the election.

The conventional wisdom is that most voters treat contested judicial elections like retention elections. Since they know nothing about either candidate, they assume that the incumbent has done an adequate job and they return him or her to the bench—probably assuming that an experienced judge is better than one without experience, and if the incumbent had in fact done something so terrible that it rendered him or her unfit to serve, the media would have reported on that fact.

As it turns out, the numbers do not exactly back up the conventional wisdom. For the lower appellate courts, incumbents face challengers so rarely that there is no reliable data on the advantages of incumbency. And in Supreme Court elections, a 25% rate of rejecting incumbents certainly shows a strong advantage for incumbents, but is not quite the “rubber stamp” predicted by the conventional wisdom.

Retention elections
Finally, seventeen states use the retention election system, in which the sitting judge’s name appears on the ballot by itself, and the voter merely decides whether or not to retain the judge or remove him or her from office (if a majority of voters decide against retention, the judge is removed and a new judge is appointed, usually by the governor).

As might be expected, retention rates are extraordinarily high. One survey studied 5,894 retention elections from 1964-2004 and found that only 55 (0.9%) were not retained. (29 of these 55 were from the state of Illinois, which requires a 60% vote to retain a judge).

The average percentage of people who vote to retain their judges has varied between 72% and 84% for the last fifty years, generally hovering around 75%.