Author! Author! Author...

We were interested to read your report that the number of authors per published paper has significantly increased in the past 20 years ("The expanding universe of scientific authorship", 8 July), and that some of this might have been due to the pressure to include people in research assessments. Is there any evidence that more multi-authoring is taking place in any other type of academic output?

R.E. Heff; Juan Starr; Rhys Urch; Ray Tings; Si Tation-Count; Hayley C. Lektiv; C.V. Filla; May Dupnames (and Mark Griffiths, professor of gambling studies, Nottingham Trent University).