Interesting #s from the AHA

The American Historical Association's professional magazine, Perspectives, features an interesting essay on current tenure practices: Robert Townsend, "A Survey of Tenure Practices in History: Departments Indicate Books Are Key and Success Rates for Tenure High," Perspectives 42.2 (Feb. 2004): 5-8. Townsend crunches the numbers from 441 respondents (both research and teaching campuses). Some percentages:

• According to his first table, "Tenure Success Rates," the overall average tenure rates ranged from 92.3% (Ph.D.-granting schools) to 97% (MA-granting schools). As Townsend notes in some bemusement, "these rates seem exceptionally high" (5). Nevertheless, as he also points out, approximately 1/3 of all campuses lack tenure altogether (8 n. 2).
  
• According to Table 3, 37.7% of all campuses combined required a book for tenure; 59.5% said a book would help (7). These numbers don't quite match up with the article's subtitle, do they?
  
• By contrast, 55.8% of all campuses required publications in refereed journals (7).
  
• Only 1.4% required a second book, although 90% said it would help (7).
  

The last item suggests that the fabled "two books for tenure" requirement, while it certainly exists, is hardly of epidemic proportions; indeed, many schools require no books at all. (For that matter, one can't help but notice that some schools apparently have no publication requirements whatsoever.) It would be interesting to see the statistics for English departments.