TITLE: How often do people read the work that they cite?
QUESTION [55 upvotes]: I have the following question:

How likely it is that an author carefully read through a paper cited by him?

Not everyone reads through everything that they have cited. Sometimes, if one wants to use a theorem that is not in a standard textbook, one typically finds another paper which cites the desired result and copies that citation thereby passing the responsibility of ensuring correctness to someone else. This saves a lot of time, but seems to propagate inaccurate citations and poor understanding of the work being cited.
The question is thus about what should authors' citing policy be, and to what extent authors should verify results they are citing rather than using them as black boxes.

REPLY [12 votes]: [offtopic] Since I cannot comment, let me just throw in an old story I heard from my professor. Some time back, a paper by Einstein and Preuss was being cited all around. Now, we all know some names that collaborated with Einsten, but this Preuss is kinda unknown. Turns out that the journal name of the reference
Einstein, A. (1931). Sitzungsber. Preuss. Akad. Wiss. ...
after some citations, got to be promoted to coauthor. NICE!
Here's some (german) reference: http://de.wikipedia.org/wiki/S._B._Preuss
Now just to account to the statistics, I know some people that skip the reading of some papers to present seminars and talks, but I think they do check the stuff before writing something up. As to me, I try to read some stuff and then check the references and references of references until I give up. But that doesn't matter, since I'm far from publish anything at all, as it seems. Cheers.