  Naively, one would expect longer papers to have larger impact (i.e., to be
cited more). I tested this expectation by selecting all (~30,000) refereed
papers from A&A, AJ, ApJ and MNRAS published between 2000 and 2004. These
particular years were chosen so papers analyzed would not be too "fresh", but
at the same time length of each article could be obtained via ADS. I find that
indeed longer papers published in these four major astronomy journals are on
average cited more, with a median number of citations increasing from 6 for
articles 2-3 pages long to about 50 for articles ~50 pages long. I do however
observe a significant "Letters effect", i.e. ApJ and A&A articles 4 pages long
are cited more than articles 5-10 pages long. Also, the very few longest (>80
pages) papers are actually cited less than somewhat shorter papers. For
individual journals, median citations per paper increase from 11 for ~9,300 A&A
papers to 14 for ~5,300 MNRAS papers, 16 for ~2,550 AJ papers, and 20 for
~12,850 ApJ papers (including ApJ Letters and Supplement). I conclude with some
semi-humorous career advice, directed especially at first-year graduate
students.
