Here's the website for the book: http://www.us.oup.com/us/catalog/general/subject/Law/?view=usa&view=usa&ci=9780199542475.

I think those points are all well-taken. I would push you, though, to think more about the factors that go into the ABA rating. I mentioned that I think your measure of prior career as a Congressional staffer might be one way to operationalize the criterion of "judicial temperament." How else might one measure that idea? In it, the ABA discusses open-mindedness, sympathy to minority interests, etc. Is there a way to include those ideas in your model? You also discuss the time-boundedness and I accept your decision to focus only on the current state of things. However, I think it is an interesting question whether or not it is truly the case that the bias has switched over time in these ratings. In addition, I think the way in which you measure ideology could be more nuanced, perhaps focusing on some measure of the ideological makeup of the committee itself and its relationship to the ideology of the nominee, which could then be applied to any committee at any point in time. Perhaps the ratings are driven by the same forces that drive Senators to vote for or against a given nominee -- ideological distance coupled with qualifications. (See, e.g., Cameron, Cover and Segal 1990)