Friday, December 08, 2006

Do Ethicists Steal More Books? More Data

I've finished collecting data relevant to the question of whether ethics books are more likely to be missing from libraries than non-ethics books in philosophy. You might think ethics books would vanish at a lower rate, if the people interested in them were influenced by the contents! (See this post for some earlier discussion.)

I was led to gather these data by what I call The Problem of the Ethics Professors -- the fact, or apparent fact, that ethics professors seem to behave no better than the rest of us. This is perhaps one small, imperfect way of assessing the presupposition behind that question. If I'm wrong, and ethicists really do behave better than the rest of us, perhaps this will reveal itself in their library habits?

It doesn't. For this analysis, I constructed a list of ethics books in philosophy and a comparison list of non-ethics books. The ethics list was derived from all the ethics books reviewed in Philosophical Review from 1990-2001 -- mostly technical work in philosophy principally of interest to advanced graduate students and professors -- combined with all the books originally published after 1959 that appear it at least five different bibliographies in the ethics entries in the Stanford Encyclopedia of Philosophy (including political philosophy, legal philosophy, and history of ethics, but excluding philosophy of action and moral psychology). The comparison list was composed of about 1/3 of the non-ethics books from the same issues of Phil Review (randomly selected, and excluding philosophy of action, moral psychology, and philosophy of religion), combined with books appearing in at least five different SEP entries on philosophy of mind or language (excluding philosophy of action and moral psychology).

I then looked at the holdings of these books at the libraries in UC Berkeley, UC Irvine, UCLA, UC Riverside, UC San Diego, UC Santa Cruz, Harvard, Stanford, Princeton, Columbia, Cornell, Michigan, and Texas, as well as all the COPAC libraries in Britian, which includes all the major university libraries. (I won't get into the principles of library selection.) A paid research assistant helped me with some of this!

I sorted the information into five categories: On shelf; checked out but not overdue; overdue one year or less; "missing" or more than one year overdue (which I will interpret as also missing); uninterpretable (e.g., "record unavailable").

Here are the uninterpreted numbers:
Ethics books:
Total holdings: 14,551
Total out or missing: 3,708
Total overdue or missing: 780
Total missing: 305

Non-ethics books:
Total holdings: 9,584
Total out or missing: 1,764
Total overdue or missing: 176
Total missing: 113

Obviously more ethics books are overdue and missing, but of course more are also held and checked out. The most interesting figures, I think, are these:

Overdue or missing, as a percentage of those off shelf:
Ethics: 21.0%
Non-ethics: 10.0%

Missing, as a percentage of those off shelf:
Ethics: 8.2%
Non-ethics: 6.4%

An ethics book is more than twice as likely to be overdue, given that it is off the shelf, and about 25% more likely to be missing!

The first difference is statistically significant at p < .001, the second at p = .02, using a simple one-proportion test (two-tailed, of course!).

Now obviously there are confounds. I'm trying to work on straightening those out, and I'll hopefully report more on them next week. I'd be interested to hear suggestions for further analyses.

Here are three worries I have:
(1.) Ethics books are more checked out than non-ethics books, and there is a correlation in the data between number checked out and percentage of those off shelf that are missing or overdue.
(2.) Older books are more likely to be missing than more recent books, and the weighted average age of the ethics books (weighted by number of checkouts) is about two years earlier than that of non-ethics books (1989 vs. 1991).
(3.) It might be those pesky law students! How will things look if I exclude philosophy of law texts or exclude results from law schools?

As far as I can tell from preliminary analysis, controlling for (2) or (3) slightly reduces the effect, but a statistically significant difference remains. Controlling for (1) seems to eliminate the second effect, but not the first.


John Linarelli said...

Hey Eric, do you not know the ancient Chinese adage, to steal a book is an elegant offense? These ethicists may not be doing anything wrong, or at most they commit a minor offense.

Great blog, by the way.

John Linarelli

Justin Tiwald said...

Thanks for this, Eric. It's nice to see you make a statistical foray into this issue, instead of casting about for anecdotal evidence (one of my favorite pastimes, but admittedly less informative than this).

I worry that the influence of the law students and legal scholars will be hard to control for. You're right to think that they cite ethics texts quite liberally, especially those that address issues in political philosophy or rational choice theory. And there are many (many!) more law students than career ethicists or aspiring career ethicists. Since only a small number of these actually do serious work in ethics, it seems very likely to skew the results. Can you see any reason to think otherwise?

Eric Schwitzgebel said...

Thanks for the comments, John and Justin!

I guess I disagree with you, John, about stealing books from libraries! Although obviously it's not a grave offense, I do think it's non-trivial. Students (and procrastinating faculty) often have short deadlines for writing essays. If a crucial book is missing from the collection, that can be a substantial inconvenience -- especially if the fact that it is missing is not discovered until after a recall or search has already failed.

Justin: I agree that the law students issue could be a big problem, especially if we assume that law students are tapping the general collection and not just the law libraries. My hope, though, is that if we look specifically at law libraries (which probably have mostly law students and faculty checkouts) and don't see a much higher theft rate there, then we can hope the law student effect isn't the principal thing going on. I'm also thinking of sorting texts into those most connected with law and those of little likely interest to most law students and seeing if there's a big effect.

In any case, even if the law student effect ends up washing out the main effect, I'm actually not that attached to the main effect. I'm not, in fact, inclinded to think that ethicists are more vicious than the rest of us. Even if theft rates are in the end about the same, I think that raises interesting questions about the relationship between philosophical reflection on ethics and moral behavior.

Anonymous said...

But it would get more attention if you demonstrated that ethics students and professors are MORE unethical.

You could write some article comparing them to accountants who know how to cheat the law. And publish a few books on it heh. There is probably a large audience out there willing to pay money to read about how they have been found to be superior ethically to ethics experts.


Eric Schwitzgebel said...

I agree, GeniusNZ, that showing ethicists to be less ethical than non-ethicists would be sexier, and more interesting in a certain way. The problem is, I don't believe it; and I think it's theoretically interesting enough that they are no better.

However, I am open to persuasion. Doing further analysis on my ethics books data, it's looking like none of the three worries I have are sufficient to explain the data -- that, in fact, ethics books are more likely to be stolen than non-ethics books, even when I eliminate those other sources of influence. (I plan to post on this in the first week of the new year.)

Anonymous said...

We recently completed a full stockcheck (our first in several years) and by a large margin the law collections suffered the highest number of "disappearances".

In one collection (I think it was Law Reference), around 25% of stock was missing and unaccounted for.

In all the subject collections, the rate of loss for reference titles was around double that for loanable items from the same collection.

Eric Schwitzgebel said...

Thanks for that tidbit, Dave. I think that's compatible with my findings. If law books and ethics books are stolen about about the same rate, and ethics books are stolen more than other books, then you'd expect law libraries to have more missing books than general libraries do (since in the latter ethics books are only a small proportion, of course).

On the other hand, though, I think it's problematic to compare across disciplines. The book use habits of physicists, historians, literature professors, and lawyers may be very different (e.g., in the use of reference texts); and higher or lower "missing" rates may reflect differences in those practices at least as much as differences in conscience.

It's also problematic, I think, to look at just one library, since incidental facts about book assignments in courses, or one particularly unconscientious professor who moved away with 300 books (as recently happened at UC Riverside, according to the head of our circulation department!) could drive the effect.