1. Fitts’s Law
Incredibly professional presentation by Thomas Gin, someone please hire me

2. Introduction Created by American psychologist Paul Fitts
Law that predicts the average time for someone to move and interact with some target
Mathematical equation

3. Fitts’s Law
MT = a + b (ID)

4. ID = log2(2D/W) Index of Difficulty
ID = way of measuring difficulty of selecting a target
D = distance from starting point to center of target
W = width of the target from axis of motion

5. ID = log2(2D/W) Index of Difficulty
Difficulty of interaction increases when the target is farther away
Difficulty of interaction decreases when the target is larger

6. Why 2D Instead of D??
“The use of 2A rather than A is indicated by both logical and practical considerations. Its use insures that the index will be greater than zero for all practical situations and has the effect of adding one bit (-log21/2) per response to the difficulty index. The use of 2A makes the index correspond rationally to the number of successive fractionations required to specify the tolerance range out of a total range extending from the point of initiation of a movement to a point equidistant on the opposite side of the target.”
- notable smart man, Paul Fitts

7. MT = a + b (ID) = a + b log2(2D/W)
Fitts’s Law
MT = a + b (ID) = a + b log2(2D/W)
MT = average time to complete movement
a = constant for starting/stopping time of the device
b = constant for inherent speed of the device

8. IP = (ID/MT) or IP = 1/b Index of Performance
IP = way of measuring human performance
Fitts’ version is the first one
MT = a + ID/IP

9. Takeaways from Fitts’s Law
Important targets should be larger
Buttons > hyperlinks
Make radio button text clickable
Users have small areas of attention
Keep tasks and task relevant targets close together
Targets in corners and screen edges are easier to hit due to limitations on movement

10. Takeaways from Fitts’s Law
Consider how users will read your webpage when placing elements
Linear menus can take longer to navigate
Radial menus give equal importance to all clickable elements
Doesn’t only apply to mouse based movement or even computers

11. (Give me applause, I require validation)
THE END
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