A few observations on turns in the Sotomayor debate.
First, there has been some preliminary skirmishing over her "reversal" rate. While I think that Supreme Court treatment of her decisions can be instructive, a simple calculation of percentage of cases that were reversed is probably not going to get us very far. The United States Supreme Court is not an error-correcting court and tends to take only those cases in which the law needs clarification. Its disposition of those cases is often going to be divided (i.e., the Justices themselves will not agree) and it is, therefore, a bit off to say that reversal means an appellate court judge was "wrong" at least in the sense of performing incompetently or making some sort of mistake.
Analysis of reversals can, however, tell us something about a judge's philosophy or political orientation. If (assuming sufficient numbers), a judge is reversed more than others in a period in which the Court is thought to be "liberal" or "conservative," that may be instructive. If a judge's votes are highly correlated with those of conservative justices, that may tell us something. If (and, again, this assumes sufficient numbers), a judge is frequently reversed by a unanimous or near unanimous court, it could be a relevant bit of information.
For related reasons, I am not overly impressed by anecdotes or statistical analysis purporting to show that Judge Sotomayor reached "conservative" results, e.g., by ruling against a discrimination claim. There are two principal objections to placing a great deal of weight on such claims.
First, there is a huge difference between sitting on the Court of Appeals and serving on the Supreme Court. An Circuit Court judge ought to follow Supreme Court precedent. A justice ought to respect it, but may vote to overturn or modify it.
The second reason is related to the problem with overly simple uses of "reversal rates." Most cases aren't that hard. It is a relatively small percentage in which judges of different philosophical bents will differ.
But those are precisely the cases that the Supreme Court takes. I don't have the numbers, but it as judges on the D.C. Circuit Court of Appeals, Ruth Bader Ginsburg and Antonin Scalia may have agreed fairly often. On the Supreme Court, they may have been far more likely to disagree. What may have seemed like a minor philosophical difference now looks far more significant.