With Judge Sonia Sotomayor already facing questions over her 60 percent reversal rate, the Supreme Court could dump another problem into her lap next month if, as many legal analysts predict, the court overturns one of her rulings upholding a race-based employment decision.There are two fairly obvious problems with this. Firstly, only five of Sotomayor's opinions have been ruled upon by the Supreme Court. That's hardly enough to reach a statistically sound conclusion. Moreover, as a matter of semantics, most people don't begin quoting percentages until the number of instances is significantly higher than five. If you came into the office on a Monday morning, and I asked you whether you'd gotten out over the weekend, you probably wouldn't say: "Yes, I got out 66.67% of the time!" -- you'd just tell me that you went out on Friday and Saturday and then sat around and watched basketball on Sunday.
Three of the five majority opinions written by Judge Sotomayor for the 2nd Circuit Court of Appeals and reviewed by the Supreme Court were reversed, providing a potent line of attack raised by opponents Tuesday after President Obama announced he will nominate the 54-year-old Hispanic woman to the high court.
"Her high reversal rate alone should be enough for us to pause and take a good look at her record. Frankly, it is the Senates duty to do so," said Wendy Wright, president of Concerned Women for America.
But secondly, a 60 percent reversal rate is actually below average based on the Washington Times' criteria. According to MediaMatters.org, the Supreme Court typically reverses about 75 percent of circuit court decisions that it chooses to rule upon.
The reason that the reversal rate is so high, of course, is that the Supreme Court has a lot of discretion about which cases it chooses to review and rule upon, and is generally not going to be inclined to overturn law dictated by a lower court unless the legal reasoning is substantially questionable and has a strong chance of reversal. The better metric would probably be the number of decisions that the Supreme Court overturned out of all of Sotomayor's majority opinions -- whether the Court elected to review them in detail or not. According to the terrific SCOTUSBLOG, "Since joining the Second Circuit in 1998, Sotomayor has authored over 150 opinions, addressing a wide range of issues, in civil cases". Even if we do not count the opinions she has authored in criminal, rather than civil, cases, that means the Supreme Court's reversal rate is not 60 percent, but at most 2 percent -- 3 cases out of 150. I have no idea whether that figure is above average, below average, or somewhere in between, but three reversals in more than a decade's worth of jurisprudence strikes this layman as being an extremely solid track record.
EDIT: For a better informed (although not uniformly favorable) statistical take on Sotomayor's jurisprudence, see Eugene Volokh's post here.