John Lott has some interesting numbers on Alito's tenure on the Court of Appeals. I thought this was sort of interesting:
Law professors Stephen Choi of New York University and Mitu Gulati of Georgetown University did a study of the circuit court judges appointed from the administration of presidents Jimmy Carter through the first term of Bill Clinton on several issues. Among them was whether a judge votes in lockstep with other judges nominated by the same political party. They found that Alito was the 12th-most politically independent Republican of the 55 that they studied. If he had been a Democrat, his ranking would have made him the eighth- most politically independent out of 42.
Alito has had some influence on the most important legal issue of the day, ranking about in the middle of the circuit court judges based on how frequently the Supreme Court cites his decisions. He also works hard, placing in the top 30 percent based on the number of opinions he has written. His legal background is stellar: a graduate of Yale Law School, he served on the law review, clerked for the circuit court, and is widely published in law journals.
For those less quantitatively inclined:
The Almanac of the Federal Judiciary regularly surveys lawyers who practice before federal judges. Half of those surveyed viewed him as politically neutral; all of those polled thought he had a good judicial temperament.
Professor Frank Cross challenges Lott's interpretation of Choi and Gulati in the Comments:
Perhaps unsurprisingly, this review by John Lott is quite misleading. Under Choi & Gulati's citation-based measure of judicial quality, Alito comes out very poorly, well down in the bottom half of all circuit court judges. That was their primary measure, and Lott doesn't mention it. Now, I've got a forthcoming paper that argues that this measure is an unreliable one and Alito suffers not for lack of quality but because it is a minimalist. But it's still misleading to cite a couple of categories where he does well but ignore their leading category, where he did quite poorly.
And independence in their study doesn't mean judicial independence, or anything like it. His high score here probably just means that 3rd Circuit Republicans are pretty liberal, as has been noted on this blog, so he is more likely to disagree with them and write a conservative opinion.