“…All of the empirical evaluation papers in the ¢rst nine years of UMUAI can be classi¢ed into four broad topic areas: ten papers in adaptive-hypermedia/information-¢ltering (Jennings and Higuchi, 1993;Kaplan et al, 1993;Boyle and Encarnacion, 1994;Vassileva, 1996;Mathe¨and Chen, 1996;Raskutti et al, 1997;Newell, 1997;Hirashima et al, 1997;Alspector et al, 1997;Balabanovic¨, 1998), nine in student modeling (Nwana, 1991;London, 1992;Carbonaro et al, 1995;Corbett and Anderson, 1995;Kashihara et al, 1995;Shute, 1995;Webb and Kuzmycz, 1996;Mitrovic et al, 1996;Milne et al, 1996;Sison et al, 1998), nine in plan recognition/mixed-initiative interaction (Calistri-Yeh, 1991;Albrecht et al, 1998;Gmytrasiewicz et al, 1998;Chiu and Webb, 1998;Chu-Carroll and Brown, 1998;Guinn, 1998;Ishizaki et al, 1999;Green and Carberry, 1999;Virvou and du Bulay, 1999), and three in user interfaces/help systems (Tattersall, 1992;Krause et al, 1993;Debevc et al, 1996).…”