“…Strong fit of model has been empirically supported by many experiments (Douglas et al, 1999;Soukoreff and Mackenzie, 2004). The model was investigated from information theoretic view (Fitts, 1954;Mackenzie, 1989;Chan and Childress, 1990), from kinesthetic view and control theory (Connelly, 1984). Also, several studies have elaborated to come up with better index of difficulty (Fitts, 1954;Crossman, 1956;Welford et al, 1969).…”