1. Buy the Human Factors person lunch

2. GOMS Model • Goals • Objects • Methods • Selection • 1980s – Card, Moran, and Newell

3. Interface timings • K = 0.2 sec • Keying, The time it takes to tape a key • P = 1.1 sec • Pointing, The time it takes a user to point to a position on the display • H = 0.4 sec • Homing, The time it takes a user’s hand to point from the keyboard to the GUI • M = 1.35 sec • Mentally preparing, the time it takes a user to prepare for the next step

4. GOMS example • Hamburger ordering • say that {cheese, mustard, ketchup, pickle} can be added to the burger • Then, (1)we need to move the hand, “H” add a “M”, select cheese “K”, select mustard “K”. Select a number of burgers “M”, “K”, “S”coll and “K” • HMKK M KSK = H + 2M + 4K + S • .4 + 2(1.35) + 4(.2) + 3 = 6.9 seconds

5. Fitts’ Law • Fitts estimates the time a user will take to point to a target (e.g.,button) • The longer the target is from the current cursor position, the longer it takes to move to the target. • The smaller the target, the more time it takes the user to find it.

6. Hicks Law • The more targets the user has to choose, the more time it takes to pick one.